add a LightsBuffer structure for use in shader programs

src/tangerine.cpp

@@ -10,21 +10,25 @@
 
 bool initGraphics(SDLHandles* handles);
 
+LightsBuffer initLights(MemoryArena* arena, GLContext* gl_ctx, u32 max_lights);
 
 
 // interface
 
 RenderState*
-initRenderState(u32 max_models,
+initRenderState(GLClearColor clear_col,
+	u32 max_models,
 	u32 max_textures,
 	u32 max_shaders,
 	u32 max_render_groups,
-	u32 max_ubos)
+	u32 max_ubos,
+	u32 max_lights)
 {
 	LOGF(Info, "Initializing Renderer\n");
 	RenderState* rs = UTIL_ALLOC(1, RenderState);
 
 	if (rs) {
+		rs->clear_col = clear_col;
 		rs->assets.arena = arenaInit(DEFAULT_ARENA_SIZE);
 		rs->assets.max_models = max_models;
 		rs->assets.models = ARENA_ALLOC(rs->assets.arena, Model, max_models);
@@ -48,10 +52,11 @@ initRenderState(u32 max_models,
 				max_ubos);
 
 		rs->xforms = ARENA_ALLOC(rs->assets.arena, Transforms, 1);
+		GLBuffer* xforms_ubo = getFreeUBO(rs->gl_ctx);
+		assert(xforms_ubo);
+		initTransforms(rs->assets.arena, rs->xforms, xforms_ubo, rs->gl_ctx);
 
-		// FIXME: need to test this with another shader that has another UBO
-		GLBuffer& ubo = rs->gl_ctx->uniform_buffers[rs->gl_ctx->num_ubos++];
-		initTransforms(rs->assets.arena, rs->xforms, &ubo, rs->gl_ctx);
+		rs->lights_buf = initLights(rs->rg_arena, rs->gl_ctx, max_lights);
 
 		bool ret = loadDefaultShaders(rs);
 		assert(ret);
@@ -285,3 +290,39 @@ initGraphics(SDLHandles* handles)
 	return handles->window != nullptr;
 }
 
+LightsBuffer
+initLights(MemoryArena* arena, GLContext* gl_ctx, u32 max_lights)
+{
+	// FIXME: revisit for 'Scene' abstraction
+	LightsBuffer lights_buf;
+	lights_buf.max_p_lights = max_lights;
+	lights_buf.max_d_lights = max_lights;
+	lights_buf.p_lights = ARENA_ALLOC(arena, PointLight, max_lights);
+	lights_buf.d_lights = ARENA_ALLOC(arena, PointLight, max_lights);
+
+	GLBuffer* lights_ubo = getFreeUBO(gl_ctx);
+	assert(lights_ubo);
+
+	lights_ubo->target = GL_UNIFORM_BUFFER;
+	lights_ubo->data_type = GL_BYTE;	// NOTE: mixed types in structure
+	lights_ubo->name = arenaCopyCStr(arena, "lights");
+	assert((GLint) gl_ctx->binding_count < gl_ctx->max_binding_points);
+	lights_ubo->binding_idx = gl_ctx->binding_count++;
+
+	// FIXME: need to pad any vec3s to vec4 to match layout std140
+	u32 buf_size = sizeof(LightsBuffer)
+				+ max_lights * sizeof(PointLight)
+				+ max_lights * sizeof(PointLight);
+	glGenBuffers(1, &lights_ubo->id);
+	glBindBuffer(lights_ubo->target, lights_ubo->id);
+	glBufferData(lights_ubo->target,
+				buf_size,
+				&lights_buf,
+				GL_DYNAMIC_DRAW);
+	glBindBufferBase(lights_ubo->target,
+					lights_ubo->binding_idx,
+					lights_ubo->id);
+
+	return lights_buf;
+}
+

src/tangerine.h

@@ -136,9 +136,12 @@ struct RenderState
 	// 	could have render groups, lights, camera
 	// 	could match up with gltf scene graph where everyting is part of a node
 	// TODO: will also need other types of lights: directional, spotlight
+	LightsBuffer lights_buf;
+#if 0
 	u32 num_lights;
 	u32 max_lights;
 	PointLight* lights;
+#endif
 };
 
 
@@ -147,11 +150,15 @@ struct RenderState
 #define DEFAULT_SHADER_COUNT 64
 #define DEFAULT_UBO_COUNT 32
 #define DEFAULT_RENDER_GROUP_COUNT 256
-RenderState* initRenderState(u32 max_models = DEFAULT_MODEL_COUNT,
+#define DEFAULT_CLEAR_COLOR { 0.2, 0.2, 0.2, 1 }
+#define DEFAULT_MAX_LIGHTS 32 // NOTE: needs to match NUM_LIGHTS in shaders
+RenderState* initRenderState(GLClearColor clear_col = DEFAULT_CLEAR_COLOR,
+	u32 max_models = DEFAULT_MODEL_COUNT,
 	u32 max_textures = DEFAULT_TEXTURE_COUNT,
 	u32 max_shaders = DEFAULT_SHADER_COUNT,
 	u32 max_render_groups = DEFAULT_RENDER_GROUP_COUNT,
-	u32 max_ubos = DEFAULT_UBO_COUNT);
+	u32 max_ubos = DEFAULT_UBO_COUNT,
+	u32 max_lights = DEFAULT_MAX_LIGHTS);
 
 void freeRenderState(RenderState*& rs);