mirror of
https://github.com/glest/glest-source.git
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455 lines
13 KiB
C++
455 lines
13 KiB
C++
// ==============================================================
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// This file is part of MegaGlest (www.glest.org)
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//
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// Shader.cpp -- Copyright (c) 2006-2007 David Henry
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// changed for use with MegaGlest: Copyright (C) 2011- by Mark Vejvoda
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//
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// This code is licenced under the MIT license.
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//
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// This software is provided "as is" without express or implied
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// warranties. You may freely copy and compile this source into
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// applications you distribute provided that the copyright text
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// below is included in the resulting source code.
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//
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// Implementation of GLSL shader related classes.
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//
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/////////////////////////////////////////////////////////////////////////////
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#include <iostream>
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#include <fstream>
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#include "ShaderManager.h"
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#include "GlErrors.h"
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namespace Shared { namespace Graphics { namespace md5 {
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using std::cout;
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using std::cerr;
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using std::endl;
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/////////////////////////////////////////////////////////////////////////////
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//
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// Global shader related functions.
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//
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/////////////////////////////////////////////////////////////////////////////
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static GLboolean GLSLCapable = GL_FALSE;
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// --------------------------------------------------------------------------
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// hasShaderSupport
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//
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// Return true if the host has GLSL, so that we can use shaders.
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// --------------------------------------------------------------------------
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GLboolean hasShaderSupport () {
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return GLSLCapable;
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}
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// --------------------------------------------------------------------------
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// checkExtensionPresence
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//
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// Check if an extension is present on the host OpenGL implementation.
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// Increment @missing if the extension is missing.
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// --------------------------------------------------------------------------
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static void checkExtensionPresence (const string &name, int &missing) {
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if (!glewIsSupported (name.c_str ()))
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{
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cerr << "* missing " << name << " extension" << endl;
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missing++;
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}
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}
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// --------------------------------------------------------------------------
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// initShaderHandling
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//
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// Initialize variables and extensions needed for using GLSL. This
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// function should be called before any shader usage (at application
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// initialization for example).
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// --------------------------------------------------------------------------
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void initShaderHandling () {
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int missing = 0;
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// Check for extensions needed for GLSL support on host
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checkExtensionPresence ("GL_ARB_shader_objects", missing);
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checkExtensionPresence ("GL_ARB_shading_language_100", missing);
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checkExtensionPresence ("GL_ARB_vertex_shader", missing);
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checkExtensionPresence ("GL_ARB_fragment_shader", missing);
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// Disable GLSL if one extension is missing
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if (missing > 0)
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GLSLCapable = GL_FALSE;
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else
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GLSLCapable = GL_TRUE;
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}
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/////////////////////////////////////////////////////////////////////////////
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//
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// class Shader implementation.
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//
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/////////////////////////////////////////////////////////////////////////////
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// --------------------------------------------------------------------------
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// Shader::Shader
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//
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// Constructor.
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// --------------------------------------------------------------------------
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Shader::Shader (const string &filename)
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: _name (filename), _handle (0), _compiled (0) {
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}
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// --------------------------------------------------------------------------
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// Shader::~Shader
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//
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// Destructor. Destroy the shader handle.
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// --------------------------------------------------------------------------
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Shader::~Shader () {
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if (GLEW_VERSION_2_0)
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{
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if (glIsShader (_handle))
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glDeleteShader (_handle);
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}
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else
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{
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GLint type;
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glGetObjectParameterivARB (_handle, GL_OBJECT_TYPE_ARB, &type);
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if (GL_SHADER_OBJECT_ARB == type)
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glDeleteObjectARB (_handle);
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}
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}
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// -------------------------------------------------------------------------
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// Shader::printInfoLog
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//
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// Print log info about a vertex or a fragment shader.
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// -------------------------------------------------------------------------
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void Shader::printInfoLog () const {
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GLint infologLength = 0;
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// First check for previous OpenGL errors...
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checkOpenGLErrors (__FILE__, __LINE__);
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// Get log's length
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if (GLEW_VERSION_2_0)
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glGetShaderiv (_handle, GL_INFO_LOG_LENGTH, &infologLength);
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else
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glGetObjectParameterivARB (_handle, GL_OBJECT_INFO_LOG_LENGTH_ARB,
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&infologLength);
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// If log is empty, quit
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if (infologLength <= 1)
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return;
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try
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{
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GLchar *infoLog = new GLchar[infologLength];
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// Get the log...
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if (GLEW_VERSION_2_0)
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glGetShaderInfoLog (_handle, infologLength, NULL, infoLog);
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else
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glGetInfoLogARB (_handle, infologLength, NULL, infoLog);
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// ...and print it to standard output
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cout << "Shader \"" << _name << "\" InfoLog ("
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<< infologLength << "):" << endl << infoLog << endl;
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delete [] infoLog;
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}
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catch (std::bad_alloc &err)
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{
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cerr << "Error: memory allocation failed for shader info log"
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<< endl << " Reason: " << err.what () << endl;
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}
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}
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// -------------------------------------------------------------------------
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// Shader::compile
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//
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// Create and compile the shader.
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// -------------------------------------------------------------------------
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void Shader::compile ()
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throw (std::runtime_error) {
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const GLchar *code = _code.c_str ();
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if (GLEW_VERSION_2_0)
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{
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// Create a shader object
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_handle = glCreateShader (shaderType ());
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// Upload shader code to OpenGL
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glShaderSource (_handle, 1, &code, NULL);
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// Compile shader
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glCompileShader (_handle);
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glGetShaderiv (_handle, GL_COMPILE_STATUS, &_compiled);
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printInfoLog ();
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// Check for success
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if (GL_FALSE == _compiled)
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throw std::runtime_error ("Compilation failed");
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}
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else
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{
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// Create a shader object
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_handle = glCreateShaderObjectARB (shaderType ());
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// Upload shader code to OpenGL
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glShaderSourceARB (_handle, 1, &code, NULL);
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// Compile shader
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glCompileShaderARB (_handle);
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glGetObjectParameterivARB (_handle, GL_OBJECT_COMPILE_STATUS_ARB, &_compiled);
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printInfoLog ();
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// Check for success
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if (GL_FALSE == _compiled)
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throw std::runtime_error ("Compilation failed");
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}
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}
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// -------------------------------------------------------------------------
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// Shader::loadShaderFile
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//
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// Load shader's GLSL code from file. The code is stored into the
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// _code string member variable.
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// -------------------------------------------------------------------------
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void Shader::loadShaderFile (const string &filename) throw (std::runtime_error) {
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// Open the file
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std::ifstream ifs (filename.c_str (), std::ios::in | std::ios::binary);
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if (ifs.fail ())
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throw std::runtime_error ("Couldn't open shader file: " + filename);
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// Read whole file into string
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_code.assign (std::istreambuf_iterator<char>(ifs),
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std::istreambuf_iterator<char>());
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// Close file
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ifs.close ();
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}
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/////////////////////////////////////////////////////////////////////////////
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//
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// class VertexShader implementation.
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//
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/////////////////////////////////////////////////////////////////////////////
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// --------------------------------------------------------------------------
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// VertexShader::VertexShader
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//
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// Constructor. Read vertex shader code from file and compile it.
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// --------------------------------------------------------------------------
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VertexShader::VertexShader (const string &filename)
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: Shader (filename) {
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try
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{
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// Load shader code from file
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loadShaderFile (filename);
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// Compile the shader
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compile ();
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cout << "* Vertex shader \"" << _name << "\" compiled" << endl;
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}
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catch (std::runtime_error &err)
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{
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cerr << "Error: Faild to create vertex shader from " << _name << endl;
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cerr << "Reason: " << err.what () << endl;
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}
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}
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/////////////////////////////////////////////////////////////////////////////
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//
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// class FragmentShader implementation.
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//
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/////////////////////////////////////////////////////////////////////////////
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// --------------------------------------------------------------------------
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// FragmentShader::FragmentShader
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//
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// Constructor. Read fragment shader code from file and compile it.
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// --------------------------------------------------------------------------
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FragmentShader::FragmentShader (const string &filename)
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: Shader (filename) {
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try
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{
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// Load shader code from file
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loadShaderFile (filename);
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// Compile the shader
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compile ();
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cout << "* Fragment shader \"" << _name << "\" compiled" << endl;
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}
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catch (std::runtime_error &err)
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{
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cerr << "Error: Faild to create fragment shader from " << _name << endl;
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cerr << "Reason: " << err.what () << endl;
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}
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}
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/////////////////////////////////////////////////////////////////////////////
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//
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// class ShaderProgram implementation.
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//
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/////////////////////////////////////////////////////////////////////////////
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// --------------------------------------------------------------------------
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// ShaderProgram::ShaderProgram
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//
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// Constructor. Link vertex and fragment shader. If the vertex shader
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// or the fragment shader is invalid (has failed to compile), the
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// shader program creation is aborted.
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// --------------------------------------------------------------------------
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ShaderProgram::ShaderProgram (const string &filename,
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const VertexShader &vertexShader,
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const FragmentShader &fragmentShader)
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: _name (filename), _handle (0), _linked (0) {
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try {
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if (vertexShader.fail ())
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throw std::runtime_error ("Invalid vertex shader");
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if (fragmentShader.fail ())
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throw std::runtime_error ("Invalid fragment shader");
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if (GLEW_VERSION_2_0)
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{
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// Create program and attach vertex and fragment shaders
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_handle = glCreateProgram ();
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glAttachShader (_handle, vertexShader.handle ());
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glAttachShader (_handle, fragmentShader.handle ());
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// Perform link stage
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glLinkProgram (_handle);
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glGetProgramiv (_handle, GL_LINK_STATUS, &_linked);
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// Validate program
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glValidateProgram (_handle);
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printInfoLog ();
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// Check for success
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if (GL_FALSE == _linked)
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throw std::runtime_error ("Link stage failed");
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}
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else
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{
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// Create program and attach vertex and fragment shaders
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_handle = glCreateProgramObjectARB ();
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glAttachObjectARB (_handle, vertexShader.handle ());
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glAttachObjectARB (_handle, fragmentShader.handle ());
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// Perform link stage
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glLinkProgramARB (_handle);
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glGetObjectParameterivARB (_handle, GL_OBJECT_LINK_STATUS_ARB, &_linked);
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// Validate program
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glValidateProgramARB (_handle);
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printInfoLog ();
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// Check for success
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if (GL_FALSE == _linked)
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throw std::runtime_error ("Link stage failed");
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}
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cout << "* Shader \"" << _name << "\" successfully linked" << endl;
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}
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catch (std::runtime_error &err)
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{
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cerr << "Error: Faild to create shader " << _name << endl;
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cerr << "Reason: " << err.what () << endl;
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}
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}
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// --------------------------------------------------------------------------
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// ShaderProgram::~ShaderProgram
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//
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// Destructor. Destroy the shader program handle.
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// --------------------------------------------------------------------------
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ShaderProgram::~ShaderProgram () {
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if (GLEW_VERSION_2_0)
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{
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if (glIsProgram (_handle))
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glDeleteProgram (_handle);
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}
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else
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{
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GLint type;
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glGetObjectParameterivARB (_handle, GL_OBJECT_TYPE_ARB, &type);
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if (GL_PROGRAM_OBJECT_ARB == type)
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glDeleteObjectARB (_handle);
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}
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}
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// -------------------------------------------------------------------------
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// ShaderProgram::use
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// ShaderProgram::unuse
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//
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// Bind/unbind the shader.
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// -------------------------------------------------------------------------
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void ShaderProgram::use () const {
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if (GLEW_VERSION_2_0)
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glUseProgram (_handle);
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else
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glUseProgramObjectARB (_handle);
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}
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void ShaderProgram::unuse () const {
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if (GLEW_VERSION_2_0)
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glUseProgram (0);
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else
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glUseProgramObjectARB (0);
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}
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// -------------------------------------------------------------------------
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// ShaderProgram::printInfoLog
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//
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// Print log info about a shader program.
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// -------------------------------------------------------------------------
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void ShaderProgram::printInfoLog () const {
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GLint infologLength = 0;
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// First check for previous OpenGL errors...
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checkOpenGLErrors (__FILE__, __LINE__);
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// Get log's length
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if (GLEW_VERSION_2_0)
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glGetProgramiv (_handle, GL_INFO_LOG_LENGTH, &infologLength);
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else
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glGetObjectParameterivARB (_handle, GL_OBJECT_INFO_LOG_LENGTH_ARB,
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&infologLength);
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// If log is empty, quit
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if (infologLength <= 1)
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return;
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try
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{
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GLchar *infoLog = new GLchar[infologLength];
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// Get the log...
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if (GLEW_VERSION_2_0)
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glGetProgramInfoLog (_handle, infologLength, NULL, infoLog);
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else
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glGetInfoLogARB (_handle, infologLength, NULL, infoLog);
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// ...and print it to standard output
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cout << "Program \"" << _name << "\" InfoLog ("
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<< infologLength << "):" << endl << infoLog << endl;
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delete [] infoLog;
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}
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catch (std::bad_alloc &err)
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{
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cerr << "Error: memory allocation failed for shader program "
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<< "info log" << endl << " Reason: " << err.what () << endl;
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}
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}
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}}} //end namespace
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