src/opengl/glutils_funcs.cpp

0001 /*
0002     KWin - the KDE window manager
0003     This file is part of the KDE project.
0004
0005     SPDX-FileCopyrightText: 2007 Rivo Laks <rivolaks@hot.ee>
0006
0007     SPDX-License-Identifier: GPL-2.0-or-later
0008 */
0009
0010 #include "opengl/glplatform.h"
0011 #include "opengl/glutils.h"
0012
0013 // Resolves given function, using getProcAddress
0014 // Useful when functionality is defined in an extension with a different name
0015 #define GL_RESOLVE_WITH_EXT(function, symbolName) \
0016     function = (function##_func)resolveFunction(#symbolName);
0017
0018 namespace KWin
0019 {
0020
0021 static GLenum GetGraphicsResetStatus();
0022 static void ReadnPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format,
0023                         GLenum type, GLsizei bufSize, GLvoid *data);
0024 static void GetnUniformfv(GLuint program, GLint location, GLsizei bufSize, GLfloat *params);
0025
0026 // GL_ARB_robustness / GL_EXT_robustness
0027 glGetGraphicsResetStatus_func glGetGraphicsResetStatus;
0028 glReadnPixels_func glReadnPixels;
0029 glGetnUniformfv_func glGetnUniformfv;
0030
0031 void glResolveFunctions(const std::function<resolveFuncPtr(const char *)> &resolveFunction)
0032 {
0033     const bool haveArbRobustness = hasGLExtension(QByteArrayLiteral("GL_ARB_robustness"));
0034     const bool haveExtRobustness = hasGLExtension(QByteArrayLiteral("GL_EXT_robustness"));
0035     bool robustContext = false;
0036     if (GLPlatform::instance()->isGLES()) {
0037         if (haveExtRobustness) {
0038             GLint value = 0;
0039             glGetIntegerv(GL_CONTEXT_ROBUST_ACCESS_EXT, &value);
0040             robustContext = (value != 0);
0041         }
0042     } else {
0043         if (haveArbRobustness) {
0044             if (hasGLVersion(3, 0)) {
0045                 GLint value = 0;
0046                 glGetIntegerv(GL_CONTEXT_FLAGS, &value);
0047                 if (value & GL_CONTEXT_FLAG_ROBUST_ACCESS_BIT_ARB) {
0048                     robustContext = true;
0049                 }
0050             } else {
0051                 robustContext = true;
0052             }
0053         }
0054     }
0055     if (robustContext && haveArbRobustness) {
0056         // See https://www.opengl.org/registry/specs/ARB/robustness.txt
0057         GL_RESOLVE_WITH_EXT(glGetGraphicsResetStatus, glGetGraphicsResetStatusARB);
0058         GL_RESOLVE_WITH_EXT(glReadnPixels, glReadnPixelsARB);
0059         GL_RESOLVE_WITH_EXT(glGetnUniformfv, glGetnUniformfvARB);
0060     } else if (robustContext && haveExtRobustness) {
0061         // See https://www.khronos.org/registry/gles/extensions/EXT/EXT_robustness.txt
0062         glGetGraphicsResetStatus = (glGetGraphicsResetStatus_func)resolveFunction("glGetGraphicsResetStatusEXT");
0063         glReadnPixels = (glReadnPixels_func)resolveFunction("glReadnPixelsEXT");
0064         glGetnUniformfv = (glGetnUniformfv_func)resolveFunction("glGetnUniformfvEXT");
0065     } else {
0066         glGetGraphicsResetStatus = KWin::GetGraphicsResetStatus;
0067         glReadnPixels = KWin::ReadnPixels;
0068         glGetnUniformfv = KWin::GetnUniformfv;
0069     }
0070 }
0071
0072 static GLenum GetGraphicsResetStatus()
0073 {
0074     return GL_NO_ERROR;
0075 }
0076
0077 static void ReadnPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format,
0078                         GLenum type, GLsizei bufSize, GLvoid *data)
0079 {
0080     glReadPixels(x, y, width, height, format, type, data);
0081 }
0082
0083 static void GetnUniformfv(GLuint program, GLint location, GLsizei bufSize, GLfloat *params)
0084 {
0085     glGetUniformfv(program, location, params);
0086 }
0087
0088 } // namespace