bool ShaderProgram::build() {
m_needsBuild = false;
m_generation = s_validGeneration;
// Inject source blocks
std::string vertSrc = m_vertexShaderSource;
std::string fragSrc = m_fragmentShaderSource;
applySourceBlocks(vertSrc, fragSrc);
// Try to compile vertex and fragment shaders, releasing resources and quiting on failure
GLint vertexShader = makeCompiledShader(vertSrc, GL_VERTEX_SHADER);
if (vertexShader == 0) {
return false;
}
GLint fragmentShader = makeCompiledShader(fragSrc, GL_FRAGMENT_SHADER);
if (fragmentShader == 0) {
glDeleteShader(vertexShader);
return false;
}
// Try to link shaders into a program, releasing resources and quiting on failure
GLint program = makeLinkedShaderProgram(fragmentShader, vertexShader);
if (program == 0) {
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
return false;
}
// New shaders linked successfully, so replace old shaders and program
if (m_glProgram == s_activeGlProgram) {
glUseProgram(0);
s_activeGlProgram = 0;
}
// Delete handles for old shaders and program; values of 0 are silently ignored
glDeleteShader(m_glFragmentShader);
glDeleteShader(m_glVertexShader);
glDeleteProgram(m_glProgram);
m_glFragmentShader = fragmentShader;
m_glVertexShader = vertexShader;
m_glProgram = program;
// Clear any cached shader locations
m_attribMap.clear();
m_uniformMap.clear();
return true;
}
bool ShaderProgram::buildFromSourceStrings(const std::string& _fragSrc, const std::string& _vertSrc) {
std::string glslHeader = "#ifdef GL_ES\nprecision mediump float;\n#endif\n\n";
std::string vertSrc = glslHeader + _vertSrc;
std::string fragSrc = glslHeader + _fragSrc;
// Try to compile vertex and fragment shaders, releasing resources and quiting on failure
GLint vertexShader = makeCompiledShader(vertSrc, GL_VERTEX_SHADER);
if (vertexShader == 0) {
return false;
}
GLint fragmentShader = makeCompiledShader(fragSrc, GL_FRAGMENT_SHADER);
if (fragmentShader == 0) {
glDeleteShader(vertexShader);
return false;
}
// Try to link shaders into a program, releasing resources and quiting on failure
GLint program = makeLinkedShaderProgram(fragmentShader, vertexShader);
if (program == 0) {
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
return false;
}
// New shaders linked successfully, so replace old shaders and program
if (m_glProgram == s_activeGlProgram) {
glUseProgram(0);
s_activeGlProgram = 0;
}
glDeleteShader(m_glFragmentShader);
glDeleteShader(m_glVertexShader);
glDeleteProgram(m_glProgram);
m_glFragmentShader = fragmentShader;
m_glVertexShader = vertexShader;
m_glProgram = program;
// Make copies of the shader source code inputs, for this program to keep
m_fragmentShaderSource = std::string(_fragSrc);
m_vertexShaderSource = std::string(_vertSrc);
// Clear any cached shader locations
m_attribMap.clear();
m_uniformMap.clear();
return true;
}
