add simple mesh, render object, and shader types

examples/Makefile

@@ -7,7 +7,10 @@ LIB = ../build/libTangerine.a
 BINDIR = bin
 
 
-all: mkdirs $(OBJDIR)/hello_world.o $(OBJDIR)/assimp_loading.o
+all: mkdirs \
+	$(OBJDIR)/hello_world.o \
+	$(OBJDIR)/assimp_loading.o \
+	$(OBJDIR)/simple_mesh.o
 .PHONY: all
 
 -include $(OBJDIR)/*.d
@@ -24,6 +27,10 @@ $(OBJDIR)/assimp_loading.o: $(LIB)
 	$(CXX) $(CXXFLAGS) -c -MMD assimp_loading/main.cpp -o $@
 	$(CXX) -o $(BINDIR)/assimp_loading $(LDFLAGS) $@ $(LIB)
 
+$(OBJDIR)/simple_mesh.o: $(LIB)
+	$(CXX) $(CXXFLAGS) -c -MMD simple_mesh/main.cpp -o $@
+	$(CXX) -o $(BINDIR)/simple_mesh $(LDFLAGS) $@ $(LIB)
+
 clean:
 	rm -rf $(OBJDIR)/* bin/*
 .PHONY: clean

examples/assimp_loading/main.cpp

@@ -4,8 +4,9 @@
 
 #include "camera.h"
 #include "dumbLog.h"
-#include "renderer.h"
 #include "entity.h"
+#include "renderer.h"
+#include "shader_program.h"
 
 
 void
@@ -27,7 +28,8 @@ main()
 	}
 
 	// TODO: this needs to be more convenient
-	rs->render_groups = renAllocateGroup(1, *rs->default_shader);
+	shader_wrapper sw = { DEFAULT_SHADER, rs->default_shader, nullptr };
+	rs->render_groups = renAllocateGroup(1, sw);
 	rs->render_group_count = 1;
 	entity& spaceship = rs->render_groups->entities[0];
 
@@ -48,7 +50,7 @@ main()
 	// NOTE: testing assimp animation info
 	logDebugAnimationInfo("../data/spaceship.glb");
 
-	if (entInit(spaceship, "../data/spaceship.glb")) {
+	if (entInitModel(spaceship, "../data/spaceship.glb")) {
 		// TODO: this should be handled in entInit
 		entSetWorldPosition(spaceship, glm::vec3(0, 0, 0));
 		entScale(spaceship, glm::vec3(20, 20, 20));

examples/simple_mesh/main.cpp

@@ -0,0 +1,54 @@
+
+#include <glm/glm.hpp>
+
+#include "dumbLog.h"
+#include "mesh.h"
+#include "renderer.h"
+
+
+int
+main()
+{
+	render_state* rs = renInit("simple mesh");
+
+	if (rs == nullptr) {
+		LOG(Error) << "Error Initialzing renderer\n";
+		return 1;
+	}
+
+	// TODO: this needs to be more convenient
+	shader_wrapper sw = { SIMPLE_SHADER, nullptr, rs->simple_shader };
+	rs->render_groups = renAllocateGroup(1, sw);
+	rs->render_group_count = 1;
+
+	entity& e = rs->render_groups->entities[0];
+	// manually construct a simple mesh
+	simple_mesh mesh = {0};
+	mesh.num_vertices = 4;
+	mesh.vertices = UTIL_ALLOC(mesh.num_vertices, glm::vec3);
+	mesh.vertices[0] = glm::vec3(-200, 0, 200);
+	mesh.vertices[1] = glm::vec3(-200, 0, -200);
+	mesh.vertices[2] = glm::vec3(200, 0, -200);
+	mesh.vertices[3] = glm::vec3(200, 0, 200);
+	mesh.vert_colors = UTIL_ALLOC(mesh.num_vertices, glm::vec3);
+	mesh.vert_colors[0] = glm::vec3(255, 0, 0);
+	mesh.vert_colors[1] = glm::vec3(255, 0, 0);
+	mesh.vert_colors[2] = glm::vec3(255, 0, 0);
+	mesh.vert_colors[3] = glm::vec3(255, 0, 0);
+	//initialize entity with new mesh
+	entInitSimpleMesh(e, mesh, GL_LINE_LOOP);
+	utilSafeFree(mesh.vertices);
+	utilSafeFree(mesh.vert_colors);
+
+	cameraInitPerspective(
+		rs->cam,
+		glm::vec3(0, -500, 0),
+		glm::vec3(0, 0, 0),
+		glm::vec3(0,0,1)
+	);
+
+	renDoRenderLoop(rs);
+
+	renShutdown(rs);
+	return 0;
+}

include/entity.h

@@ -7,19 +7,32 @@
 #include "render_object.h"
 
 
+enum mesh_group_type
+{
+	DEFAULT_MESHES = 0,
+	SIMPLE_MESH = 1
+};
+
 struct entity
 {
 	glm::mat4 world_transform;
 
+	mesh_group_type mesh_type;
+
+	simple_mesh mesh;
+	simple_render_object simple_ro;
+	GLenum draw_mode;
+
 	// TODO: should be a pointer into a global array of mesh_info(s) or
 	// 	mesh_groups stored on the render_state object
 	mesh_group meshes;
-
 	render_object* render_objs;
 	uint ro_count;
 };
 
-bool entInit(entity& e, const char* model_path);
+bool entInitModel(entity& e, const char* model_path);
+
+bool entInitSimpleMesh(entity& e, simple_mesh& mesh, GLenum draw_mode);
 
 void entFree(entity& e);
 

include/lights.h

@@ -30,5 +30,5 @@ void lightsOut(light_group* lights);
 bool
 lightsAdd(light_group* lights, glm::vec3 pos, glm::vec3 color, float intensity);
 
-void lightsUpdate(light_group* lights, shader_program* shader);
+void lightsUpdate(light_group* lights, default_shader_program* shader);
 

include/mesh.h

@@ -34,6 +34,13 @@ struct mesh_group
 	uint num_meshes;
 };
 
+struct simple_mesh
+{
+	glm::vec3* vertices;
+	glm::vec3* vert_colors;
+	uint num_vertices;
+};
+
 
 bool meInitAssimp();
 
@@ -43,5 +50,7 @@ bool meLoadFromFile(mesh_group& mesh_group, const char* filepath);
 
 void meFreeMeshGroup(mesh_group& mesh_group);
 
+void meFreeSimpleMesh(simple_mesh& mesh);
+
 void meShutdownAssimp();
 

include/render_object.h

@@ -19,14 +19,31 @@ struct render_object
 	GLuint normal_buffer_id;
 	GLuint uv_buffer_id;
 	GLuint index_buffer_id;
-	GLuint index_buffer_count;
+	uint index_buffer_count;
+};
+
+struct simple_render_object
+{
+	GLuint vertex_buffer_id;
+	GLuint vertex_color_buffer_id;
+	uint vertex_count;
 };
 
 bool roInit(mesh_info* mi_in, render_object& ro_out);
 
+bool roInitSimpleMesh(simple_mesh& mesh_in, simple_render_object& ro_out);
+
 void roFree(render_object& ro);
 
+void roFreeSimple(simple_render_object& ro);
+
 void roDraw(render_object& ro,
 	camera& cam,
-	shader_program& shader,
+	default_shader_program& shader,
 	light_group* lights);
+
+void roDrawSimple(simple_render_object& ro,
+	camera& cam,
+	simple_shader_program& shader,
+	GLenum draw_mode);
+

include/renderer.h

@@ -26,10 +26,11 @@ struct SDL_Handles
 // NOTE: array of entities rendered with the same shader program
 struct render_group
 {
+	// TODO: also needs to be resizable
 	entity* entities;
 	uint entity_count;
 
-	shader_program shader;
+	shader_wrapper shader;
 };
 
 struct render_state
@@ -44,7 +45,9 @@ struct render_state
 	render_group* render_groups;
 	uint render_group_count;
 
-	shader_program* default_shader;
+	default_shader_program* default_shader;
+	simple_shader_program* simple_shader;
+
 	light_group* lights;
 };
 
@@ -55,15 +58,13 @@ renInit(const char* title = "Tangerine",
 void renShutdown(render_state* rs);
 
 render_group*
-renAllocateGroup(uint entity_count, shader_program shader);
+renAllocateGroup(uint entity_count, shader_wrapper shader);
 
-//
 typedef void (*frame_callback_fn) (render_state*);
 
 void renDoRenderLoop(render_state* rs,
 	uint framerate = 60,
 	frame_callback_fn cb_func = nullptr);
-//
 
 void renRenderFrame(render_state* rs);
 

include/shader_program.h

@@ -4,7 +4,7 @@
 #include <GL/glew.h>
 
 
-struct shader_program
+struct default_shader_program
 {
 	GLuint program_id;
 
@@ -18,6 +18,36 @@ struct shader_program
 	GLuint num_lights_id;
 };
 
-shader_program* shaderInit(const char* vertex_code, const char* frag_code);
+struct simple_shader_program
+{
+	GLuint program_id;
+	GLuint MVP_id;
+	GLuint vertex_array_id;
+};
+
+enum shader_type
+{
+	SIMPLE_SHADER = 0,
+	DEFAULT_SHADER = 1
+};
+
+struct shader_wrapper
+{
+	shader_type type;
+	default_shader_program* default_shader;
+	simple_shader_program* simple_shader;
+};
+
+
+// TODO: find a way to initialize different shaders with different
+// 	uniform layouts with a single function
+//	look at using uniform blocks and retrieving locations with
+//	glGetUniformBlockIndex() and their size with glGetActiveUniformBlockiv()
+//	see chapter 2 in the red book
+simple_shader_program*
+shaderInitSimple(const char* vertex_code, const char* frag_code);
+
+default_shader_program*
+shaderInitDefault(const char* vertex_code, const char* frag_code);
 
-void shaderFree(shader_program* shader);
+void shaderFree(uint program_id);

src/default_shaders.cpp

@@ -13,6 +13,7 @@ uniform mat4 model;
 uniform mat4 view;
 uniform mat4 projection;
 
+
 void main()
 {
 	fragNormal = normal;
@@ -62,3 +63,34 @@ void main()
 }
 )FS";
 
+const char* SIMPLE_VERTEX_SHADER = R"SVS(
+#version 330 core
+
+layout (location = 0) in vec3 position;
+layout (location = 1) in vec3 color;
+
+out vec3 frag_color;
+
+uniform mat4 MVP;
+
+
+void main()
+{
+	frag_color = color;
+	gl_Position = MVP * vec4(position, 1);
+}
+)SVS";
+
+const char* SIMPLE_FRAGMENT_SHADER = R"SFS(
+#version 330 core
+
+in vec3 frag_color;
+
+out vec4 color;
+
+
+void main()
+{
+	color = vec4(frag_color.rgb, 1);
+}
+)SFS";

src/entity.cpp

@@ -10,23 +10,24 @@
 
 // forward declarations
 
-bool loadMeshIntoGL(entity& e);
+void initDefaults(entity& e);
+bool loadMeshesIntoGL(entity& e);
+bool loadSimpleMeshIntoGL(entity& e);
 
 
 // interface
 
 bool
-entInit(entity& e, const char* model_path)
+entInitModel(entity& e, const char* model_path)
 {
-	e.world_transform = glm::mat4(1.0);
-	entScale(e, glm::vec3(1.0));
-	entSetWorldPosition(e, glm::vec3(0, 0, 0));
+	initDefaults(e);
+	e.mesh_type = DEFAULT_MESHES;
 
 	if (meLoadFromFile(e.meshes, model_path))
 	{
 		e.ro_count = e.meshes.num_meshes;
 		e.render_objs = UTIL_ALLOC(e.ro_count, render_object);
-		if (loadMeshIntoGL(e))
+		if (loadMeshesIntoGL(e))
 			return true;
 	}
 
@@ -34,10 +35,40 @@ entInit(entity& e, const char* model_path)
 	return false;
 }
 
+bool
+entInitSimpleMesh(entity& e, simple_mesh& mesh, GLenum draw_mode)
+{
+	assert(mesh.num_vertices > 0);
+	initDefaults(e);
+	e.mesh_type = SIMPLE_MESH;
+	e.draw_mode = draw_mode;
+
+	e.mesh.num_vertices = mesh.num_vertices;
+	e.mesh.vertices = UTIL_ALLOC(mesh.num_vertices, glm::vec3);
+	e.mesh.vert_colors = UTIL_ALLOC(mesh.num_vertices, glm::vec3);
+
+	for (uint i = 0; i < mesh.num_vertices; i++) {
+		e.mesh.vertices[i] = mesh.vertices[i];
+		e.mesh.vert_colors[i] = mesh.vert_colors[i];
+	}
+
+	if (loadSimpleMeshIntoGL(e))
+		return true;
+
+	entFree(e);
+	return false;
+}
+
 void
 entFree(entity& e)
 {
-	meFreeMeshGroup(e.meshes);
+	if (e.mesh_type == DEFAULT_MESHES)
+		meFreeMeshGroup(e.meshes);
+
+	if (e.mesh_type == SIMPLE_MESH) {
+		meFreeSimpleMesh(e.mesh);
+		roFreeSimple(e.simple_ro);
+	}
 
 	for (uint i = 0; i < e.ro_count; i++)
 		roFree(e.render_objs[i]);
@@ -75,8 +106,16 @@ entScale(entity& e, glm::vec3 v)
 
 // internal
 
+void
+initDefaults(entity& e)
+{
+	e.world_transform = glm::mat4(1.0);
+	entScale(e, glm::vec3(1.0));
+	entSetWorldPosition(e, glm::vec3(0, 0, 0));
+}
+
 bool
-loadMeshIntoGL(entity& e)
+loadMeshesIntoGL(entity& e)
 {
 	for (uint i = 0; i < e.meshes.num_meshes; i++) {
 		assert(e.render_objs != nullptr);
@@ -94,3 +133,15 @@ loadMeshIntoGL(entity& e)
 	return true;
 }
 
+bool
+loadSimpleMeshIntoGL(entity& e)
+{
+	assert(e.mesh.num_vertices > 0);
+
+	if (roInitSimpleMesh(e.mesh, e.simple_ro))
+		return true;
+
+	LOG(Error) << "Error initializing render object\n";
+	entFree(e);
+	return false;
+}

src/lights.cpp

@@ -37,7 +37,7 @@ lightsAdd(light_group* lights, glm::vec3 pos, glm::vec3 color, float intensity)
 }
 
 void
-lightsUpdate(light_group* lights, shader_program* shader)
+lightsUpdate(light_group* lights, default_shader_program* shader)
 {
 	glUniform1ui(shader->num_lights_id, lights->num_lights);
 

src/mesh.cpp

@@ -78,6 +78,16 @@ meFreeMeshGroup(mesh_group& mesh_group)
 	mesh_group.meshes = nullptr;
 }
 
+void
+meFreeSimpleMesh(simple_mesh& mesh)
+{
+	utilSafeFree(mesh.vertices);
+	mesh.vertices = nullptr;
+	utilSafeFree(mesh.vert_colors);
+	mesh.vert_colors = nullptr;
+	mesh.num_vertices = 0;
+}
+
 void
 meShutdownAssimp()
 {

src/render_object.cpp

@@ -11,7 +11,8 @@ bool initGLFloatBuffer(glm::vec3* buffer, uint count, GLuint& buffer_id);
 bool initGLIndexBuffer(uint* buffer, uint num_indices, GLuint& buffer_id);
 bool initGLTexture(const util_image image, GLuint& tex_id);
 inline void
-updateMatrices(shader_program& shader, camera& cam, glm::mat4 node_xform);
+updateMatrices(default_shader_program& shader, camera& cam,
+	glm::mat4 node_xform);
 inline void enableGLFloatBuffer(uint buffer_id, uint location);
 
 
@@ -44,6 +45,25 @@ roInit(mesh_info* mi_in, render_object& ro_out)
 	return false;
 }
 
+bool
+roInitSimpleMesh(simple_mesh& mesh_in, simple_render_object& ro_out)
+{
+	if (initGLFloatBuffer(mesh_in.vertices,
+			mesh_in.num_vertices,
+			ro_out.vertex_buffer_id) &&
+		initGLFloatBuffer(mesh_in.vert_colors,
+			mesh_in.num_vertices,
+			ro_out.vertex_color_buffer_id))
+	{
+		ro_out.vertex_count = mesh_in.num_vertices;
+		return true;
+	}
+
+	LOG(Error) << "Failed to initialize render_object\n";
+	roFreeSimple(ro_out);
+	return false;
+}
+
 void
 roFree(render_object& ro)
 {
@@ -54,10 +74,17 @@ roFree(render_object& ro)
 	glDeleteTextures(1, &ro.tex_id);
 }
 
+void
+roFreeSimple(simple_render_object& ro)
+{
+	glDeleteBuffers(1, &ro.vertex_buffer_id);
+	glDeleteBuffers(1, &ro.vertex_color_buffer_id);
+}
+
 void
 roDraw(render_object& ro,
 	camera& cam,
-	shader_program& shader,
+	default_shader_program& shader,
 	light_group* lights)
 {
 	glUseProgram(shader.program_id);
@@ -82,6 +109,22 @@ roDraw(render_object& ro,
 	glUseProgram(0);
 }
 
+void
+roDrawSimple(simple_render_object& ro,
+	camera& cam,
+	simple_shader_program& shader,
+	GLenum draw_mode)
+{
+	glUseProgram(shader.program_id);
+	glUniformMatrix4fv(shader.MVP_id, 1, GL_FALSE, &cam.MVP[0][0]);
+	enableGLFloatBuffer(ro.vertex_buffer_id, 0);
+	enableGLFloatBuffer(ro.vertex_color_buffer_id, 1);
+	glDrawArrays(draw_mode, 0, ro.vertex_count);
+	glDisableVertexAttribArray(0);
+	glDisableVertexAttribArray(1);
+	glUseProgram(0);
+}
+
 // internal
 
 bool
@@ -129,14 +172,18 @@ initGLTexture(const util_image image, GLuint& tex_id)
 // 	frame, maybe add another interface function in render_object to call from
 // 	renRenderFrame
 inline void
-updateMatrices(shader_program& shader, camera& cam, glm::mat4 node_xform)
+updateMatrices(default_shader_program& shader,
+	camera& cam,
+	glm::mat4 node_xform)
 {
 	glUniformMatrix4fv(shader.model_matrix_id, 1, GL_FALSE, &node_xform[0][0]);
 	glUniformMatrix4fv(shader.view_matrix_id, 1, GL_FALSE, &cam.view[0][0]);
-	glUniformMatrix4fv(shader.projection_matrix_id, 1, GL_FALSE, &cam.projection[0][0]);
-
-	glm::mat3 normal_matrix = glm::transpose(glm::inverse(glm::mat3(cam.model)));
-	glUniformMatrix3fv(shader.normal_matrix_id, 1, GL_FALSE, &normal_matrix[0][0]);
+	glUniformMatrix4fv(shader.projection_matrix_id, 1, GL_FALSE,
+		&cam.projection[0][0]);
+	glm::mat3 normal_matrix = glm::transpose(
+		glm::inverse(glm::mat3(cam.model)));
+	glUniformMatrix3fv(shader.normal_matrix_id, 1, GL_FALSE,
+		&normal_matrix[0][0]);
 }
 
 inline void

src/renderer.cpp

@@ -25,14 +25,15 @@
 
 
 // forward declarations
-void openglDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity,
-		GLsizei length, const GLchar* message, const void* userParam);
-bool initSDL(SDL_Handles& handles);
 bool createWindow(const char* title,
 		SDL_Handles& handles,
 		glm::vec2& viewport_dims);
 bool initContext(SDL_Handles& handles);
 bool initGlOptions();
+bool initSDL(SDL_Handles& handles);
+bool initShaders(render_state* rs);
+void openglDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity,
+		GLsizei length, const GLchar* message, const void* userParam);
 void setDefaults(render_state* rs, glm::vec2 viewport_dims);
 
 
@@ -48,17 +49,10 @@ renInit(const char* title, glm::vec2 viewport_dims)
 		createWindow(title, rs->handles, rs->viewport_dims) &&
 		initContext(rs->handles) &&
 		initGlOptions() &&
+		initShaders(rs) &&
 		meInitAssimp())
 	{
-		rs->default_shader =
-			shaderInit(DEFAULT_VERTEX_SHADER, DEFAULT_FRAGMENT_SHADER);
-
-		if (rs->default_shader != nullptr) {
-			return rs;
-		} else {
-			LOG(Error) << "shader loading failed\n";
-			return nullptr;
-		}
+		return rs;
 	}
 
 	LOG(Error) << "renderer initialization failed, aborting\n";
@@ -68,23 +62,15 @@ renInit(const char* title, glm::vec2 viewport_dims)
 void
 renShutdown(render_state* rs)
 {
-	// TODO: need a nicer way to loop over entities and render_objects
 	for (uint i = 0; i < rs->render_group_count; i++) {
-		render_group& rg = rs->render_groups[i];
-
-		for (uint j = 0; j < rg.entity_count; j++) {
-			entity& e = rg.entities[j];
-
-			for (uint k = 0; k < e.ro_count; k++)
-				roFree(e.render_objs[k]);
-
-			utilSafeFree(e.render_objs);
-		}
+		for (uint j = 0; j < rs->render_groups[i].entity_count; j++)
+			entFree(rs->render_groups[i].entities[j]);
 
-		utilSafeFree(rg.entities);
+		utilSafeFree(rs->render_groups[i].entities);
 	}
 
-	shaderFree(rs->default_shader);
+	shaderFree(rs->default_shader->program_id);
+	shaderFree(rs->simple_shader->program_id);
 	lightsOut(rs->lights);
 	utilSafeFree(rs->render_groups);
 	utilSafeFree(rs->default_shader);
@@ -95,7 +81,7 @@ renShutdown(render_state* rs)
 }
 
 render_group*
-renAllocateGroup(uint entity_count, shader_program shader)
+renAllocateGroup(uint entity_count, shader_wrapper shader)
 {
 	assert(entity_count > 0);
 	render_group* rg = UTIL_ALLOC(1, render_group);
@@ -137,20 +123,34 @@ renDoRenderLoop(render_state* rs, uint framerate, frame_callback_fn cb_func)
 void
 renRenderFrame(render_state* rs)
 {
-	glClearColor(rs->clear_col.R, rs->clear_col.G, rs->clear_col.B, rs->clear_col.A);
+	glClearColor(rs->clear_col.R,
+		rs->clear_col.G,
+		rs->clear_col.B,
+		rs->clear_col.A);
 	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
 
+	// TODO: need a nicer way to loop over entities and render_objects
+	// 	eg) entDraw()
 	for (uint i = 0; i < rs->render_group_count; i++) {
 		render_group& rg = rs->render_groups[i];
 
 		for (uint j = 0; j < rg.entity_count; j++) {
 			entity& e = rg.entities[j];
 
-			for (uint k = 0; k < e.ro_count; k++) {
-				roDraw(e.render_objs[k],
+			if (rg.shader.type == SIMPLE_SHADER) {
+				roDrawSimple(e.simple_ro,
 					rs->cam,
-					rg.shader,
-					rs->lights);
+					*rg.shader.simple_shader,
+					e.draw_mode);
+			}
+
+			if (rg.shader.type == DEFAULT_SHADER) {
+				for (uint k = 0; k < e.ro_count; k++) {
+					roDraw(e.render_objs[k],
+						rs->cam,
+						*rg.shader.default_shader,
+						rs->lights);
+				}
 			}
 		}
 	}
@@ -170,37 +170,6 @@ renAddLight(render_state* rs, glm::vec3 pos, glm::vec3 color, float intensity)
 
 // internal
 
-void
-openglDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity,
-					GLsizei length, const GLchar* message, const void* userParam)
-{
-	LOG((type == GL_DEBUG_TYPE_ERROR) ? Error : Debug)
-		<< (type == GL_DEBUG_TYPE_ERROR ? "** GL Error **" : "")
-		<< ", type: " << type
-		<< ", severity: " << severity
-		<< ", message: " << message << "\n";
-}
-
-bool
-initSDL(SDL_Handles& handles)
-{
-	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
-		LOG(Error) << "Error, SDL_Init: " << SDL_GetError() << "\n";
-		return false;
-	}
-
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG);
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
-	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
-	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
-	SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
-	SDL_GetCurrentDisplayMode(0, &handles.currentDisplayMode);
-
-	return true;
-}
-
 bool
 createWindow(const char* title, SDL_Handles& handles, glm::vec2& viewport_dims)
 {
@@ -275,6 +244,55 @@ initGlOptions()
 	return true;
 }
 
+bool
+initSDL(SDL_Handles& handles)
+{
+	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
+		LOG(Error) << "Error, SDL_Init: " << SDL_GetError() << "\n";
+		return false;
+	}
+
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
+	SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
+	SDL_GetCurrentDisplayMode(0, &handles.currentDisplayMode);
+
+	return true;
+}
+
+bool
+initShaders(render_state* rs)
+{
+	rs->default_shader =
+		shaderInitDefault(DEFAULT_VERTEX_SHADER, DEFAULT_FRAGMENT_SHADER);
+	rs->simple_shader =
+		shaderInitSimple(SIMPLE_VERTEX_SHADER, SIMPLE_FRAGMENT_SHADER);
+
+	if (rs->default_shader == nullptr ||
+		rs->simple_shader == nullptr)
+	{
+		LOG(Error) << "shader loading failed\n";
+		return false;
+	} else {
+		return true;
+	}
+}
+
+void
+openglDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity,
+					GLsizei length, const GLchar* message, const void* userParam)
+{
+	LOG((type == GL_DEBUG_TYPE_ERROR) ? Error : Debug)
+		<< (type == GL_DEBUG_TYPE_ERROR ? "** GL Error **" : "")
+		<< ", type: " << type
+		<< ", severity: " << severity
+		<< ", message: " << message << "\n";
+}
+
 void
 setDefaults(render_state* rs, glm::vec2 viewport_dims)
 {

src/shader_program.cpp

@@ -4,58 +4,130 @@
 #include "util.h"
 
 
-shader_program*
-shaderInit(const char* vertex_code, const char* frag_code)
+// forward declarations
+bool checkShaderErrors(GLuint program_id);
+void cleanUpShader(GLuint program_id, GLuint vs_id, GLuint fs_id);
+bool compileProgram(GLuint& program_id_out,
+	GLuint& vs_id_out,
+	GLuint& fs_id_out,
+	const char* vertex_code,
+	const char* frag_code);
+
+
+//interface
+
+default_shader_program*
+shaderInitDefault(const char* vertex_code, const char* frag_code)
 {
-	shader_program* sp = UTIL_ALLOC(1, shader_program);
+	default_shader_program* sp = UTIL_ALLOC(1, default_shader_program);
+	GLuint vs_id = 0;
+	GLuint fs_id = 0;
+
+	compileProgram(sp->program_id, vs_id, fs_id, vertex_code, frag_code);
 	glGenVertexArrays(1, &sp->vertex_array_id);
 	glBindVertexArray(sp->vertex_array_id);
-	GLuint vertex_shader_id = glCreateShader(GL_VERTEX_SHADER);
-	GLuint fragment_shader_id = glCreateShader(GL_FRAGMENT_SHADER);
-
-	glShaderSource(vertex_shader_id, 1, &vertex_code, NULL);
-	glShaderSource(fragment_shader_id, 1, &frag_code, NULL);
-	glCompileShader(vertex_shader_id);
-	glCompileShader(fragment_shader_id);
-
-	sp->program_id = glCreateProgram();
-	glAttachShader(sp->program_id, vertex_shader_id);
-	glAttachShader(sp->program_id, fragment_shader_id);
-	glLinkProgram(sp->program_id);
 
+	// assign uniforms
 	sp->model_matrix_id = glGetUniformLocation(sp->program_id, "model");
 	sp->view_matrix_id = glGetUniformLocation(sp->program_id, "view");
-	sp->projection_matrix_id = glGetUniformLocation(sp->program_id, "projection");
-	sp->normal_matrix_id = glGetUniformLocation(sp->program_id, "normal_matrix");
+	sp->projection_matrix_id =
+		glGetUniformLocation(sp->program_id, "projection");
+	sp->normal_matrix_id =
+		glGetUniformLocation(sp->program_id, "normal_matrix");
 	sp->num_lights_id = glGetUniformLocation(sp->program_id, "num_lights");
 	sp->sampler_id = glGetUniformLocation(sp->program_id, "sampler");
 
-	glDetachShader(sp->program_id, vertex_shader_id);
-	glDetachShader(sp->program_id, fragment_shader_id);
-	glDeleteShader(vertex_shader_id);
-	glDeleteShader(fragment_shader_id);
+	cleanUpShader(sp->program_id, vs_id, fs_id);
+
+	if (!checkShaderErrors(sp->program_id)) {
+		glDeleteProgram(sp->program_id);
+		return nullptr;
+	}
+
+	return sp;
+}
+
+simple_shader_program*
+shaderInitSimple(const char* vertex_code, const char* frag_code)
+{
+	simple_shader_program* sp = UTIL_ALLOC(1, simple_shader_program);
+	GLuint vs_id = 0;
+	GLuint fs_id = 0;
+	compileProgram(sp->program_id, vs_id, fs_id, vertex_code, frag_code);
+	// TODO: add to compile program?
+	glGenVertexArrays(1, &sp->vertex_array_id);
+	glBindVertexArray(sp->vertex_array_id);
+
+	if (!checkShaderErrors(sp->program_id)) {
+		glDeleteProgram(sp->program_id);
+		return nullptr;
+	}
+
+	return sp;
+}
 
+void
+shaderFree(uint program_id)
+{
+	// TODO: can check for valid id here
+	glDeleteProgram(program_id);
+}
+
+
+// internal
+
+bool
+checkShaderErrors(uint program_id)
+{
 	GLint isLinked = 0;
-	glGetProgramiv(sp->program_id, GL_LINK_STATUS, &isLinked);
-	if (isLinked == GL_FALSE) {
-		GLint info_len = 0;
-		glGetProgramiv(sp->program_id, GL_INFO_LOG_LENGTH, &info_len);
+	GLint info_len = 0;
+	glGetProgramiv(program_id, GL_LINK_STATUS, &isLinked);
 
+	if (isLinked == GL_FALSE) {
+		glGetProgramiv(program_id, GL_INFO_LOG_LENGTH, &info_len);
 		char* infoLog = UTIL_ALLOC(info_len, char);
-		glGetProgramInfoLog(sp->program_id, info_len, &info_len, &infoLog[0]);
+		glGetProgramInfoLog(program_id, info_len, &info_len, &infoLog[0]);
 		LOG(Error) << infoLog << "\n";
 		utilSafeFree(infoLog);
+		glDeleteProgram(program_id);
 
-		glDeleteProgram(sp->program_id);
-		return nullptr;
+		return false;
 	}
 
-	return sp;
+	return true;
 }
 
 void
-shaderFree(shader_program* shader)
+cleanUpShader(GLuint program_id, GLuint vs_id, GLuint fs_id)
+{
+	glDetachShader(program_id, vs_id);
+	glDetachShader(program_id, fs_id);
+	glDeleteShader(vs_id);
+	glDeleteShader(fs_id);
+}
+
+bool
+compileProgram(GLuint& program_id_out,
+	GLuint& vs_id_out,
+	GLuint& fs_id_out,
+	const char* vertex_code,
+	const char* frag_code)
 {
-	glDeleteProgram(shader->program_id);
+	vs_id_out = glCreateShader(GL_VERTEX_SHADER);
+	fs_id_out = glCreateShader(GL_FRAGMENT_SHADER);
+
+	glShaderSource(vs_id_out, 1, &vertex_code, NULL);
+	glShaderSource(fs_id_out, 1, &frag_code, NULL);
+	glCompileShader(vs_id_out);
+	glCompileShader(fs_id_out);
+	// TODO: can check for error here
+
+	program_id_out = glCreateProgram();
+	glAttachShader(program_id_out, vs_id_out);
+	glAttachShader(program_id_out, fs_id_out);
+	glLinkProgram(program_id_out);
+	// TODO: can check for error here
+
+	return true;
 }