/*-------------------------------------
* Setup a shader's attributes
-------------------------------------*/
bool ShaderProgramAssembly::setup_program_attribs(ShaderProgram& outProg) const noexcept {
outProg.uniforms = draw::get_shader_attribs(outProg, vertex_attrib_t::UNIFORM_ATTRIB);
outProg.vertAttribs = get_linked_shader_attribs(outProg, shader_stage_t::SHADER_STAGE_VERTEX);
outProg.fragAttribs = get_linked_shader_attribs(outProg, shader_stage_t::SHADER_STAGE_FRAGMENT);
// not bothering to support geometry shader attributes.
// Shader stages all need attributes
if (!outProg.get_vertex_attribs().get_num_attribs()) {
LS_LOG_ERR("\tFailed to introspect the vertex shader of ", outProg.gpu_id(), ".\n");
LS_DEBUG_ASSERT(false);
return false;
}
if (!outProg.get_fragment_attribs().get_num_attribs()) {
LS_LOG_ERR("\tFailed to introspect the fragment shader of ", outProg.gpu_id(), ".\n");
LS_DEBUG_ASSERT(false);
return false;
}
const GLuint shaderId = outProg.gpu_id();
GLint totalUniformBlocks = 0;
glGetProgramiv(shaderId, GL_ACTIVE_UNIFORM_BLOCKS, &totalUniformBlocks);
LS_LOG_GL_ERR();
LS_LOG_MSG("\tLocated ", totalUniformBlocks, " uniform blocks in shader ", shaderId, '.');
outProg.uniformBlocks.reset(new(std::nothrow) ShaderBlockAttrib[totalUniformBlocks]);
if (!outProg.uniformBlocks) {
LS_LOG_ERR("\tFailed to allocate space for ", totalUniformBlocks, " uniform blocks!");
LS_DEBUG_ASSERT(false);
return false;
}
for (int i = 0; i < totalUniformBlocks; ++i) {
const bool isIntrospected = outProg.uniformBlocks[i].run_block_introspection(shaderId, i);
if (!isIntrospected) {
LS_LOG_ERR("\tFailed to introspect uniform block ", i, '.');
outProg.uniformBlocks.reset();
LS_DEBUG_ASSERT(false);
return false;
}
}
outProg.numUniformBlocks = totalUniformBlocks;
return true;
}
/*-------------------------------------
* Set the vertex layout locations for an unlinked shader program
-------------------------------------*/
bool ShaderProgramAssembly::assign_shader_layouts(
const ShaderProgram& prog,
const ShaderObject& shdr
) const noexcept {
if (prog.get_attached_shader_id(shdr.get_shader_type()) != shdr.gpu_id()) {
return false;
}
// fragment shaders in OpenGLES 3.0 can't have their location manually
// specified as glBindFragDataLocation is unavailable. Geometry shaders on
// desktop GL versions should not have attribs as it increases the amount
// of required maintenance for a feature with limited support.
if (shdr.get_shader_type() != shader_stage_t::SHADER_STAGE_VERTEX) {
return true;
}
// Manually assign layout locations so OpenGL doesn't optimize out
// perfectly valid locations of variables.
const ShaderAttribArray& attribs = shdr.get_attribs();
for (unsigned i = 0; i < attribs.get_num_attribs(); ++i) {
const ShaderAttrib& attrib = attribs.get_attrib(i);
glBindAttribLocation(prog.gpu_id(), attrib.get_location(), attrib.get_name().get());
LS_LOG_GL_ERR();
}
return true;
}
/*-------------------------------------
* Attach shader objects to a program
-------------------------------------*/
bool ShaderProgramAssembly::assemble(ShaderProgram& outProg, bool runLinker) noexcept {
LS_LOG_MSG("Attempting to assemble a Shader Program.");
if (!is_assembly_valid()) {
LS_LOG_ERR("\tFailed to assemble a Shader Program. Invalid inputs shader detected.\n");
return false;
}
if (outProg.gpu_id() != 0) {
LS_LOG_ERR("\tAttempted to assemble a preexisting program object.\n");
return false;
}
else {
const GLuint progId = glCreateProgram();
LS_LOG_GL_ERR();
if (progId == 0) {
LS_LOG_ERR("\tUnable to create a handle to an OpenGL Shader Program.\n");
return false;
}
outProg.gpuId = progId;
}
glAttachShader(outProg.gpu_id(), pVertShader->gpu_id());
LS_LOG_GL_ERR();
glAttachShader(outProg.gpu_id(), pFragShader->gpu_id());
LS_LOG_GL_ERR();
#ifdef LS_DRAW_BACKEND_GL
if (pGeomShader && pGeomShader->is_valid()) {
glAttachShader(outProg.gpu_id(), pGeomShader->gpu_id());
LS_LOG_GL_ERR();
}
#endif
// Ensure all shaders attached to the program correctly
if (!assign_shader_layouts(outProg, *pVertShader)
|| !assign_shader_layouts(outProg, *pFragShader)
) {
LS_LOG_ERR(
"\tAn Error occurred while attaching a shader to the shader program ",
outProg.gpu_id(), " during assembly. The shader program will be destroyed.\n"
);
outProg.terminate();
return false;
}
LS_LOG_MSG("\tSuccessfully assembled the Shader Program ", outProg.gpu_id(), ".\n");
if (runLinker) {
return link(outProg);
}
return true;
}
/*-------------------------------------
-------------------------------------*/
bool ShaderProgramAssembly::link(ShaderProgram& outProg) const noexcept {
LS_LOG_MSG("Attempting to link the shader ", outProg.gpu_id(), '.');
GLint linkResult = 0;
glLinkProgram(outProg.gpu_id());
LS_LOG_GL_ERR();
glGetProgramiv(outProg.gpu_id(), GL_LINK_STATUS, &linkResult);
LS_LOG_GL_ERR();
GLint logLength = 0;
glGetProgramiv(outProg.gpu_id(), GL_INFO_LOG_LENGTH, &logLength);
LS_LOG_GL_ERR();
utils::Pointer <GLchar[]> logData {new GLchar[logLength + 1]};
logData[logLength] = '\0';
glGetProgramInfoLog(outProg.gpu_id(), logLength, nullptr, logData.get());
LS_LOG_GL_ERR();
LS_LOG_MSG("\tProgram linker log:\n", logData.get(), '\n');
if (linkResult != GL_TRUE) {
LS_DEBUG_ASSERT(false);
return false;
}
LS_LOG_MSG("\tSuccessfully linked shader ", outProg.gpu_id(), ". Now running introspection\n");
if (!setup_program_attribs(outProg)) {
LS_LOG_ERR("\tIntrospection of shader", outProg.gpu_id(), "failed during post-link setup.\n");
return false;
}
LS_LOG_MSG(
"\tDone. Successfully assembled and linked shader ", outProg.gpu_id(), ":",
"\n\t\tUniforms: ", outProg.uniforms.get_num_attribs(),
"\n\t\tVertex Attribs: ", outProg.vertAttribs.get_num_attribs(),
"\n\t\tFragment Attribs: ", outProg.fragAttribs.get_num_attribs(),
'\n'
);
return true;
}