void dispatch_indirect(neam::yaggler::geometry::buffer<neam::yaggler::type::opengl, BufferTypes...> buffer, size_t offset = 0)
{
if (!mw.is_empty())
{
buffer.bind_to_target(GL_DISPATCH_INDIRECT_BUFFER);
mw.use();
glDispatchComputeIndirect(offset);
}
}
void Shader::dispatchComputeShaderIndirect(GLuint dispatchBuffer, GLuint offset) const
{
glBindBuffer(GL_DISPATCH_INDIRECT_BUFFER, dispatchBuffer);
glDispatchComputeIndirect(offset);
glBindBuffer(GL_DISPATCH_INDIRECT_BUFFER, 0);
}
JNIEXPORT void JNICALL Java_org_lwjgl_opengl_GL43_nglDispatchComputeIndirect(JNIEnv *__env, jclass clazz, jlong indirect, jlong __functionAddress) {
glDispatchComputeIndirectPROC glDispatchComputeIndirect = (glDispatchComputeIndirectPROC)(intptr_t)__functionAddress;
UNUSED_PARAMS(__env, clazz)
glDispatchComputeIndirect((GLintptr)indirect);
}
JNIEXPORT void JNICALL Java_org_lwjgl_opengl_GL43_nglDispatchComputeIndirect(JNIEnv *__env, jclass clazz, jlong indirect) {
glDispatchComputeIndirectPROC glDispatchComputeIndirect = (glDispatchComputeIndirectPROC)tlsGetFunction(873);
UNUSED_PARAM(clazz)
glDispatchComputeIndirect((intptr_t)indirect);
}
JNIEXPORT void JNICALL Java_org_lwjgl_opengl_GL43_nglDispatchComputeIndirect(JNIEnv *env, jclass clazz, jlong indirect, jlong function_pointer) {
glDispatchComputeIndirectPROC glDispatchComputeIndirect = (glDispatchComputeIndirectPROC)((intptr_t)function_pointer);
glDispatchComputeIndirect(indirect);
}
void openglCompute(){
//Note: Compute shaders are only OpenGL 4.3+ so my laptop can't run this, since
//it's on 4.0
Window::init();
Window window("OpenGL Compute - Nothing will be drawn");
//This shader declares local group size to be 16x16 then does nothing
const char *doNothingSrc =
"#version 430 core \n \
//Input layout qualifier declaring a 16x16 local workgroup size \n \
//It looks like a big bonus for Opencl is being able to set this at runtime \
//Whereas in OpenGL compute shader it must be in the shader, although I suppose we could \
//change that somehow? hm \
layout (local_size_x = 16, local_size_y = 1) in; \n \
void main() { }";
std::string src = Util::readFile("../res/helloCompute.glsl");
const char *shaderSrc = src.c_str();
GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
glShaderSource(shader, 1, &shaderSrc, NULL);
glCompileShader(shader);
GLint status;
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (status != GL_TRUE){
std::cout << "Compile failed" << std::endl;
//Get the log length and then get the log
GLint logLength;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
std::vector<char> log(logLength);
glGetShaderInfoLog(shader, logLength, NULL, &log[0]);
//Construct and return log message
std::string errorMsg(log.begin(), log.end());
std::cout << errorMsg << std::endl;
}
GLuint program = glCreateProgram();
glAttachShader(program, shader);
glLinkProgram(program);
glGetProgramiv(program, GL_LINK_STATUS, &status);
if (status != GL_TRUE)
std::cout << "Link failed" << std::endl;
glDeleteShader(shader);
glUseProgram(program);
//Setup the data buffer
GLuint dataBuf;
glGenBuffers(1, &dataBuf);
glBindBuffer(GL_SHADER_STORAGE_BUFFER, dataBuf);
glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(GLuint) * 16, NULL, GL_DYNAMIC_COPY);
//Bind it as the 0th shader storage buffer binding pt
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, dataBuf);
GLuint globalDim[] = { 16, 1, 1 };
GLuint dispatchBuf;
glGenBuffers(1, &dispatchBuf);
glBindBuffer(GL_DISPATCH_INDIRECT_BUFFER, dispatchBuf);
glBufferData(GL_DISPATCH_INDIRECT_BUFFER, sizeof(globalDim), globalDim, GL_STATIC_DRAW);
glDispatchComputeIndirect(0);
Util::checkError("Dispatched compute");
int *outData = (int*)glMapBuffer(GL_SHADER_STORAGE_BUFFER, GL_READ_ONLY);
std::cout << "Data read: ";
for (int i = 0; i < 16; ++i)
std::cout << outData[i] << ", ";
std::cout << std::endl;
glUnmapBuffer(GL_SHADER_STORAGE_BUFFER);
outData = nullptr;
//cleanup
glDeleteBuffers(1, &dataBuf);
glDeleteBuffers(1, &dispatchBuf);
glDeleteProgram(program);
}
