GLMemory.cpp

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===========================================================================
*/
// GLMemory.cpp

#include "common/Common.h"

#include "GLMemory.h"

#include "gl_shader.h"

// 128 MB, should be enough to fit anything in BAR without going overboard
const GLsizeiptr GLStagingBuffer::SIZE = 128 * 1024 * 1024 / sizeof( uint32_t );

GLStagingBuffer stagingBuffer;
PushBuffer pushBuffer;

void GLBufferCopy( GLBuffer* src, GLBuffer* dst, GLintptr srcOffset, GLintptr dstOffset, GLsizeiptr size ) {
	glCopyNamedBufferSubData( src->id, dst->id,
		srcOffset * sizeof( uint32_t ), dstOffset * sizeof( uint32_t ), size * sizeof( uint32_t ) );
}

uint32_t* GLStagingBuffer::MapBuffer( const GLsizeiptr size ) {
	if ( size > SIZE ) {
		Sys::Drop( "Couldn't map GL staging buffer: size too large (%u/%u)", size, SIZE );
	}

	if ( pointer + size > SIZE ) {
		FlushAll();

		GLsync sync = glFenceSync( GL_SYNC_GPU_COMMANDS_COMPLETE, 0 );

		constexpr GLuint64 SYNC_TIMEOUT = 10000000000; // 10 seconds
		if ( glClientWaitSync( sync, GL_SYNC_FLUSH_COMMANDS_BIT, SYNC_TIMEOUT ) == GL_TIMEOUT_EXPIRED ) {
			Sys::Drop( "Failed GL staging buffer copy sync" );
		}
		glDeleteSync( sync );

		pointer = 0;
		current = 0;
		last = 0;
	}

	uint32_t* ret = buffer.GetData() + pointer;
	last = pointer;
	pointer += size;

	return ret;
}

void GLStagingBuffer::FlushBuffer() {
	buffer.FlushRange( current, pointer - current );

	GL_CheckErrors();

	current = pointer;
}

void GLStagingBuffer::QueueStagingCopy( GLBuffer* dst, const GLsizeiptr dstOffset ) {
	copyQueue[currentCopy].dst = dst;
	copyQueue[currentCopy].dstOffset = dstOffset;
	copyQueue[currentCopy].stagingOffset = last;
	copyQueue[currentCopy].size = pointer - last;

	currentCopy++;

	if ( currentCopy == MAX_COPIES ) {
		FlushStagingCopyQueue();
	}
}

void GLStagingBuffer::FlushStagingCopyQueue() {
	for ( GLStagingCopy& copy : copyQueue ) {
		if ( copy.dst ) {
			GLBufferCopy( &buffer, copy.dst, copy.stagingOffset, copy.dstOffset, copy.size );
			copy.dst = nullptr;
		}
	}

	currentCopy = 0;

	GL_CheckErrors();
}

void GLStagingBuffer::FlushAll() {
	FlushBuffer();
	FlushStagingCopyQueue();
}

bool GLStagingBuffer::Active() const {
	return buffer.id;
}

void GLStagingBuffer::InitGLBuffer() {
	buffer.GenBuffer();

	buffer.BufferStorage( SIZE, 1, nullptr );
	buffer.MapAll();

	GL_CheckErrors();
}

void GLStagingBuffer::FreeGLBuffer() {
	buffer.DelBuffer();

	pointer = 0;
	current = 0;
	last = 0;
}

void PushBuffer::InitGLBuffers() {
	globalUBO.GenBuffer();

	globalUBO.BufferStorage( pushBuffer.constUniformsSize + pushBuffer.frameUniformsSize, 1, nullptr );

	globalUBO.BindBufferBase();
}

void PushBuffer::FreeGLBuffers() {
	globalUBO.DelBuffer();
}

uint32_t* PushBuffer::MapGlobalUniformData( const int updateType ) {
	switch ( updateType ) {
		case GLUniform::CONST:
			globalUBOData = stagingBuffer.MapBuffer( constUniformsSize );
			stagingBuffer.QueueStagingCopy( &globalUBO, 0 );
			break;
		case GLUniform::FRAME:
			globalUBOData = stagingBuffer.MapBuffer( frameUniformsSize );
			stagingBuffer.QueueStagingCopy( &globalUBO, constUniformsSize );
			break;
		default:
			ASSERT_UNREACHABLE();
	}

	return globalUBOData;
}

void PushBuffer::PushGlobalUniforms() {
	stagingBuffer.FlushAll();
}