Implement constant buffers for OpenGL

Backends/Graphics4/OpenGL/Sources/kinc/backend/graphics4/OpenGL.c.h

@@ -7,6 +7,7 @@
 
 #include <kinc/backend/graphics4/vertexbuffer.h>
 
+#include <kinc/graphics4/constantbuffer.h>
 #include <kinc/graphics4/indexbuffer.h>
 #include <kinc/graphics4/pipeline.h>
 #include <kinc/graphics4/rendertarget.h>
@@ -1244,3 +1245,9 @@ bool kinc_g4_supports_non_pow2_textures() {
 bool kinc_g4_render_targets_inverted_y(void) {
 	return true;
 }
+
+#ifdef KINC_KONG
+void kinc_g4_set_constant_buffer(uint32_t id, struct kinc_g4_constant_buffer *buffer) {
+	glBindBufferBase(GL_UNIFORM_BUFFER, id, buffer->impl.buffer);
+}
+#endif

Backends/Graphics4/OpenGL/Sources/kinc/backend/graphics4/constantbuffer.c.h

@@ -0,0 +1,53 @@
+#ifdef KINC_KONG
+
+#include <kinc/graphics4/constantbuffer.h>
+
+void kinc_g4_constant_buffer_init(kinc_g4_constant_buffer *buffer, size_t size) {
+	buffer->impl.size = size;
+	buffer->impl.last_start = 0;
+	buffer->impl.last_size = size;
+
+	buffer->impl.data = malloc(size);
+
+	buffer->impl.buffer = 0;
+	glGenBuffers(1, &buffer->impl.buffer);
+	glBindBuffer(GL_UNIFORM_BUFFER, buffer->impl.buffer);
+	glBufferData(GL_UNIFORM_BUFFER, size, NULL, GL_DYNAMIC_DRAW);
+	glBindBuffer(GL_UNIFORM_BUFFER, 0);
+}
+
+void kinc_g4_constant_buffer_destroy(kinc_g4_constant_buffer *buffer) {
+	free(buffer->impl.data);
+	buffer->impl.data = NULL;
+
+	glDeleteBuffers(1, &buffer->impl.buffer);
+	buffer->impl.buffer = 0;
+}
+
+uint8_t *kinc_g4_constant_buffer_lock_all(kinc_g4_constant_buffer *buffer) {
+	return kinc_g4_constant_buffer_lock(buffer, 0, kinc_g4_constant_buffer_size(buffer));
+}
+
+uint8_t *kinc_g4_constant_buffer_lock(kinc_g4_constant_buffer *buffer, size_t start, size_t size) {
+	buffer->impl.last_start = start;
+	buffer->impl.last_size = size;
+
+	uint8_t *data = (uint8_t *)buffer->impl.data;
+	return &data[start];
+}
+
+void kinc_g4_constant_buffer_unlock_all(kinc_g4_constant_buffer *buffer) {
+	kinc_g4_constant_buffer_unlock(buffer, buffer->impl.last_size);
+}
+
+void kinc_g4_constant_buffer_unlock(kinc_g4_constant_buffer *buffer, size_t count) {
+	glBindBuffer(GL_UNIFORM_BUFFER, buffer->impl.buffer);
+	glBufferSubData(GL_UNIFORM_BUFFER, buffer->impl.last_start, buffer->impl.last_size, buffer->impl.data);
+	glBindBuffer(GL_UNIFORM_BUFFER, 0);
+}
+
+size_t kinc_g4_constant_buffer_size(kinc_g4_constant_buffer *buffer) {
+	return buffer->impl.size;
+}
+
+#endif

Backends/Graphics4/OpenGL/Sources/kinc/backend/graphics4/constantbuffer.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#ifdef KINC_KONG
+
+typedef struct kinc_g4_constant_buffer_impl {
+	unsigned buffer;
+	void *data;
+	size_t size;
+	size_t last_start;
+	size_t last_size;
+} kinc_g4_constant_buffer_impl;
+
+#endif

Backends/Graphics4/OpenGL/Sources/kinc/backend/graphics4/openglunit.c

@@ -7,6 +7,7 @@ static int kinc_internal_opengl_max_vertex_attribute_arrays = 0;
 #include "OpenGLWindow.c.h"
 #include "ShaderStorageBufferImpl.c.h"
 #include "VrInterface.c.h"
+#include "constantbuffer.c.h"
 #include "indexbuffer.c.h"
 #include "pipeline.c.h"
 #include "rendertarget.c.h"