implement buffer backed lighting uniform structure

data/full_lighting.frag

@@ -6,75 +6,50 @@ in vec2 frag_uv;
 
 out vec4 color;
 
-layout (std140) uniform matrices
-{
-	mat4 view_xform;
-	mat4 proj_xform;
-	mat4 normal_xform;
-};
-
-uniform mat4 node_xform;
 uniform sampler2D sampler;
 
-struct PointLight
-{
-	vec3 pos;
-	vec3 color;
-	uint intensity;
-};
-
-struct DirectionalLight
-{
-	vec3 direction;
-	vec3 color;
-	uint intensity;
-};
-
-// FIXME: probably want a buffer-backed UBO for lights in case we have more
-// 	than one shader that does lighting calculations
-//uniform PointLight lights[32];
-// FIXME: hard-coded values for testing
-const DirectionalLight dl1 =
-	DirectionalLight(vec3(-2, 1, 3), vec3(1,1,1), 1u);
 const vec4 ambient_color = vec4(0.1, 0.1, 0.1, 1);
-
-const PointLight pl1 = PointLight(vec3(-20, 10, 30), vec3(1, 1, 1), 800u);
-
-///
-
-
 const uint NUM_LIGHTS = 32u;
 
 layout (std140) uniform lights
 {
-	uint active_p_lights;
+	uint buf_size;
 	uint max_p_lights;
-	uint active_d_lights;
+	uint active_p_lights;
 	uint max_d_lights;
-	PointLight p_lights[NUM_LIGHTS];
-	DirectionalLight d_lights[NUM_LIGHTS];
+	uint active_d_lights;
+
+	vec4 pl_positions[NUM_LIGHTS];
+	vec4 pl_colors[NUM_LIGHTS];
+	uint pl_intensities[NUM_LIGHTS]; // NOTE: 16 bytes * NUM_LIGHTS
+
+	vec4 dl_directions[NUM_LIGHTS]; // FIXME: should be directions
+	vec4 dl_colors[NUM_LIGHTS];
+	uint dl_intensities[NUM_LIGHTS]; // NOTE: 16 bytes * NUM_LIGHTS
 };
 
 
 void main()
 {
-	for (uint i = 0u; i < NUM_LIGHTS; i++) {
-		if (p_lights[i].pos.x > 0)
-			color.r = 128;
+	// NOTE: directional lights
+	vec4 diffuse_color = vec4(0);
+
+	for (uint i = 0u; i < active_d_lights; i++) {
+		vec4 light_direction = normalize(dl_directions[i]);
+		float diffuse_factor =
+			clamp(dot(vec4(frag_normal, 1), light_direction), 0, 1);
+		diffuse_color = diffuse_color +
+			dl_intensities[i] * diffuse_factor * dl_colors[i];
 	}
 
-#if 1 // directional light
-	vec3 light_direction = normalize(dl1.direction);
-	float diffuse_factor = clamp(dot(frag_normal, light_direction), 0, 1);
-	vec4 diffuse_color = dl1.intensity * vec4(dl1.color * diffuse_factor, 1);
-#else // point light
-	vec3 light_direction = pl1.pos - frag_pos;
-	float len = length(light_direction);
-	light_direction = normalize(light_direction);
-	float diffuse_factor = dot(frag_normal, light_direction) / pow(len, 2);
-	diffuse_factor = clamp(diffuse_factor, 0, 1);
-	vec4 diffuse_color = pl1.intensity * vec4(pl1.color * diffuse_factor, 1);
-#endif
+//#else // point light
+//	vec4 light_direction = pl1.pos - frag_pos;
+//	float len = length(light_direction);
+//	light_direction = normalize(light_direction);
+//	float diffuse_factor = dot(frag_normal, light_direction) / pow(len, 2);
+//	diffuse_factor = clamp(diffuse_factor, 0, 1);
+//	vec4 diffuse_color = pl1.intensity * vec4(pl1.color * diffuse_factor);
+//#endif
 
 	color = (ambient_color + diffuse_color) * texture(sampler, frag_uv.st);
 }

src/main.cpp

@@ -4,6 +4,57 @@
 #include "tangerine.h"
 
 
+bool
+initLights(RenderState* rs)
+{
+	// NOTE: add a directional light
+	LightsBuffer* lb = rs->lights_buf;
+	u32 idx = lb->active_d_lights++;
+	lb->dl_directions[idx] = glm::vec4(-2, 1, 3, 1);
+	lb->dl_colors[idx] = glm::vec4(1, 0.8, 0.6, 1);
+	lb->dl_intensities[idx] = glm::uvec4(1, 0, 0, 0);
+
+	// FIXME: we need an interface function to get uniforms by name
+	GLBuffer* lights_ubo = nullptr;
+	for (u32 i = 0; i < rs->gl_ctx->num_ubos; i++) {
+		GLBuffer* ubo = &rs->gl_ctx->uniform_buffers[i];
+
+		// FIXME: we need a utilty function for cstring comparison that takes
+		// 	into account the length of both strings so we don't match a longer
+		// 	string with a matching prefix
+		if (strncmp(ubo->name, "lights", 8))
+			lights_ubo = ubo;
+	}
+
+	// FIXME: we need an interface function to update lights
+	glBufferSubData(lights_ubo->target, 0, lb->buf_size, lb);
+
+	// FIXME: this only makes sense for point lights
+#if 0
+	// NOTE: add a debug mesh to view the light source
+	RenderGroup* debug_group = getFreeRenderGroup(rs);
+	assert(debug_group);
+	ShaderProgram* s_debug = getShaderByName("debug", rs->gl_ctx);
+	assert(s_debug);
+	initRenderGroup(debug_group, rs->rg_arena, s_debug, 256, "debug_lights");
+	Entity* e = getFreeEntity(debug_group);
+	assert(e);
+	if (!initEntity(e,
+					rs->gl_ctx,
+					rs->rg_arena,
+					&rs->assets.models[0], // tex_cube from loadScene()
+					s_debug->num_vertex_attribs,
+					s_debug->attrib_mappings))
+	{
+		LOGF(Error, "Error initializing debug entity for light\n");
+		return false;
+	}
+
+	setEntityPosition(e, glm::vec3(lb->dl_directions[idx]));
+#endif
+	return true;
+}
+
 bool
 loadScene(RenderState* rs)
 {
@@ -56,39 +107,11 @@ loadScene(RenderState* rs)
 		scaleEntity(e, 3);
 	}
 
-	// NOTE: add a point light
-	PointLight* l1 = &rs->lights[rs->num_lights++];
-	l1->position = glm::vec3(-20, 10, 30);
-	l1->color = glm::vec3(1, 1, 1);
-	l1->intensity = 256;
-
-	// NOTE: add a debug mesh to view the light source
-	RenderGroup* debug_group = getFreeRenderGroup(rs);
-	assert(debug_group);
-	ShaderProgram* s_debug = getShaderByName("debug", rs->gl_ctx);
-	assert(s_debug);
-	initRenderGroup(debug_group, rs->rg_arena, s_debug, 256, "debug_lights");
-
-	for (u32 i = 0; i < rs->num_lights; i++) {
-		PointLight* l = &rs->lights[i];
-		Entity* e = getFreeEntity(debug_group);
-		assert(e);
-		if (!initEntity(e,
-						rs->gl_ctx,
-						rs->rg_arena,
-						tex_cube,
-						s_debug->num_vertex_attribs,
-						s_debug->attrib_mappings))
-		{
-			return false;
-		}
-
-		setEntityPosition(e, l->position);
-	}
-
-	return true;
+	return initLights(rs);
 }
 
+#include <glm/gtc/matrix_transform.hpp>
+
 void
 render_cb_pre(RenderState* rs)
 {
@@ -103,6 +126,45 @@ render_cb_pre(RenderState* rs)
 		}
 	}
 
+	// NOTE: wiggle camera
+
+	static glm::vec3 cam_pos = glm::vec3(0, 0, 50);
+	static glm::vec3 cam_mov = glm::vec3(0.3, 0, 0);
+	static glm::vec3 look_pos = glm::vec3(0, 0, 0);
+	static float direction = -1;
+
+	if (cam_pos.x < -20 || cam_pos.x > 20) {
+		direction *= -1;
+		cam_mov.x *= direction;
+	}
+
+	cam_pos += cam_mov;
+	rs->xforms->view_xform = glm::lookAt(cam_pos, look_pos, glm::vec3(0, 1, 0));
+
+#if 1
+	// TODO: make helper function for getting UBO by name in shader.h
+	static GLBuffer* xform_ubo = nullptr;
+	u64 h_search = utilFNV64a_str("matrices");
+
+	if (!xform_ubo) {
+		for (u32 i = 0; i < rs->gl_ctx->num_ubos; i++) {
+			GLBuffer* buf = &rs->gl_ctx->uniform_buffers[i];
+
+			if (buf->name != nullptr) {
+				u64 hash = utilFNV64a_str(buf->name);
+				if (hash == h_search)
+					xform_ubo = buf;
+			}
+		}
+
+		if (!xform_ubo)
+			LOGF(Error, "matrices ubo not found\n");
+	}
+
+	updateCameraTransforms(rs->xforms, xform_ubo);
+	////
+#endif
+#if 0
 	for (u32 i = 0; i < rs->num_render_groups; i++) {
 		RenderGroup& rg = rs->render_groups[i];
 
@@ -114,17 +176,17 @@ render_cb_pre(RenderState* rs)
 				direction * (float) M_PI / (3 * 60));
 		}
 	}
+#endif
 }
 
 int
 main()
 {
 	RenderState* rs = initRenderState();
-	rs->clear_col = {0.2, 0.2, 0.2, 1};
 
 	if (rs) {
 		if (!loadScene(rs)) {
-			LOG(Error) << "error loading scene\n";
+			LOGF(Error, "error loading scene\n");
 			return 1;
 		}
 
@@ -134,7 +196,7 @@ main()
 		return 0;
 	}
 
-	std::cout << "error loading scene\n";
+	LOGF(Error, "error loading scene\n");
 	return 1;
 }
 

src/shader.cpp

@@ -513,18 +513,23 @@ parseUniform(MemoryArena* arena, ShaderProgram* s, u32 uniform_idx)
 	GLUniform unif = {0};
 	GLchar unif_name[256] = {0};
 	GLsizei name_len = 0;
+	unif.idx = uniform_idx;
 
 	glGetActiveUniform(s->prog_id,
 		uniform_idx,
 		sizeof(unif_name),
 		&name_len,
 		&unif.num_elements,
-		&unif.data_type,
+		&unif.uniform_type,
 		unif_name);
-	glGetActiveUniformsiv(s->prog_id, 1, &uniform_idx,
-			GL_UNIFORM_BLOCK_INDEX, &unif.block_idx);
 
-	unif.idx = uniform_idx;
+	glGetActiveUniformsiv(s->prog_id, 1, &uniform_idx, GL_UNIFORM_BLOCK_INDEX,
+							&unif.block_idx);
+	glGetActiveUniformsiv(s->prog_id, 1, &uniform_idx, GL_UNIFORM_ARRAY_STRIDE,
+							&unif.array_stride);
+	glGetActiveUniformsiv(s->prog_id, 1, &uniform_idx, GL_UNIFORM_OFFSET,
+							&unif.uniform_offset);
+
 	unif.name = arenaCopyCStr(arena, unif_name);
 	unif.location = glGetUniformLocation(s->prog_id, unif.name);
 
@@ -712,7 +717,7 @@ parseShader(MemoryArena* arena, GLContext* gl_ctx, ShaderProgram* s)
 		return true;
 	}
 
-	LOGF(Error, "%Error parsing shader\n");
+	LOGF(Error, "Error parsing shader\n");
 	return false;
 }
 

src/shader.h

@@ -17,9 +17,16 @@ struct GLUniform
 	GLuint idx;
 	GLint location;
 	GLint block_idx;
-	GLenum data_type;
-	GLint data_size;
-	GLint num_elements;
+
+	GLenum uniform_type; // NOTE: GL_UNSIGNED_INT, GL_FLOAT_VEC4
+	GLint num_elements; // NOTE: 1 unless uniform is an array of base types
+
+	// FIXME: we can't actually get this from opengl introspection API, we have
+	// 	to infer it from the uniform type...
+	GLint data_size; // NOTE: total size in bytes...
+	GLint array_stride; // NOTE: bytes between array elements
+	GLint uniform_offset; // NOTE: byte offset from beginning of uniform
+
 	char* name;
 };
 
@@ -142,13 +149,6 @@ struct GLMesh
 
 struct Animation;
 
-struct PointLight
-{
-	glm::vec3 position;
-	glm::vec3 color;
-	u32 intensity;
-};
-
 struct Transforms
 {
 	glm::mat4 view_xform;

src/tangerine.cpp

@@ -10,7 +10,7 @@
 
 bool initGraphics(SDLHandles* handles);
 
-LightsBuffer initLights(MemoryArena* arena, GLContext* gl_ctx, u32 max_lights);
+LightsBuffer* initLights(MemoryArena* arena, GLContext* gl_ctx, u32 max_lights);
 
 
 // interface
@@ -290,17 +290,35 @@ initGraphics(SDLHandles* handles)
 	return handles->window != nullptr;
 }
 
-LightsBuffer
+LightsBuffer*
 initLights(MemoryArena* arena, GLContext* gl_ctx, u32 max_lights)
 {
 	// FIXME: revisit for 'Scene' abstraction
-	LightsBuffer lights_buf;
-	lights_buf.active_p_lights = 0;
-	lights_buf.active_d_lights = 0;
-	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);
+
+	// TODO: we need a way to do this automatically somehow
+	u32 buf_size = 8 * sizeof(u32) // NOTE: 'header'
+				+ 6 * max_lights * sizeof(glm::vec4); // NOTE: vector arrays
+
+	LOGF(Debug, "buf_size: %d\n", buf_size);
+
+	LightsBuffer* lb = (LightsBuffer*) ARENA_ALLOC(arena, u8, buf_size);
+	lb->buf_size = buf_size;
+	lb->max_p_lights = max_lights;
+	lb->max_d_lights = max_lights;
+
+	// NOTE: set offsets for array pointers
+	lb->pl_positions = (glm::vec4*) arenaGetAddressOffset(lb, 8 * sizeof(u32));
+	u32 arr_size = max_lights * sizeof(glm::vec4);
+	lb->pl_colors =
+		(glm::vec4*) arenaGetAddressOffset(lb->pl_positions, arr_size);
+	lb->pl_intensities =
+		(glm::uvec4*) arenaGetAddressOffset(lb->pl_colors, arr_size);
+	lb->dl_directions =
+		(glm::vec4*) arenaGetAddressOffset(lb->pl_intensities, arr_size);
+	lb->dl_colors =
+		(glm::vec4*) arenaGetAddressOffset(lb->dl_directions, arr_size);
+	lb->dl_intensities =
+		(glm::uvec4*) arenaGetAddressOffset(lb->dl_colors, arr_size);
 
 	GLBuffer* lights_ubo = getFreeUBO(gl_ctx);
 	assert(lights_ubo);
@@ -311,20 +329,16 @@ initLights(MemoryArena* arena, GLContext* gl_ctx, u32 max_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,
+				lb,
 				GL_DYNAMIC_DRAW);
 	glBindBufferBase(lights_ubo->target,
 					lights_ubo->binding_idx,
 					lights_ubo->id);
 
-	return lights_buf;
+	return lb;
 }
 

src/tangerine.h

@@ -109,13 +109,22 @@ struct GLClearColor
 // NOTE: structure to match the layout of the 'lights' uniform in a shader
 struct LightsBuffer
 {
-	u32 active_p_lights;
+	u32 buf_size;
 	u32 max_p_lights;
-	u32 active_d_lights;
+	u32 active_p_lights;
 	u32 max_d_lights;
-	// FIXME: do we need any padding here for layout(std 140)?
-	PointLight* p_lights;
-	PointLight* d_lights; // TODO: directional lights
+	u32 active_d_lights;
+
+	// NOTE: padding for std140, vec4 need to be aligned at 16 bytes
+	u8 padding[12];
+
+	glm::vec4* pl_positions;
+	glm::vec4* pl_colors;
+	glm::uvec4* pl_intensities;
+
+	glm::vec4* dl_directions;
+	glm::vec4* dl_colors;
+	glm::uvec4* dl_intensities;
 };
 
 struct RenderState
@@ -136,7 +145,7 @@ 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;
+	LightsBuffer* lights_buf;
 #if 0
 	u32 num_lights;
 	u32 max_lights;