Add primitive triangle rendering code

src/Asteroid.c

@@ -61,26 +61,41 @@ void initRenderer(GameState *state, v2 windowSize) {
 	GL_CHECK_ERROR();
 
 	/* Create buffers */
-	glGenVertexArrays(1, &renderer->vao);
+	glGenVertexArrays(ARRAY_COUNT(renderer->vao), renderer->vao);
-	glGenBuffers(1, &renderer->vbo);
+	glGenBuffers(ARRAY_COUNT(renderer->vbo), renderer->vbo);
 	GL_CHECK_ERROR();
 
-	/* Bind buffers */
+	{
-	glBindBuffer(GL_ARRAY_BUFFER, renderer->vbo);
+		// Bind buffers and configure vao, vao automatically intercepts
-	glBindVertexArray(renderer->vao);
+		// glBindCalls and associates the state with that buffer for us
+		glBindVertexArray(renderer->vao[rendermode_quad]);
+		glBindBuffer(GL_ARRAY_BUFFER, renderer->vbo[rendermode_quad]);
 
-	/* Configure VAO */
+		glEnableVertexAttribArray(0);
-	u32 numVertexElements = 4;
+		u32 numVertexElements = 4;
-	u32 stride            = sizeof(Vertex);
+		u32 stride            = sizeof(Vertex);
-	glVertexAttribPointer(0, numVertexElements, GL_FLOAT, GL_FALSE, stride,
-	                      (GLvoid *)0);
-	glEnableVertexAttribArray(0);
 
-	GL_CHECK_ERROR();
+		glVertexAttribPointer(0, numVertexElements, GL_FLOAT,
+		                      GL_FALSE, stride, (GLvoid *)0);
+		glBindBuffer(GL_ARRAY_BUFFER, 0);
+		glBindVertexArray(0);
+	}
+
+	{
+		glBindVertexArray(renderer->vao[rendermode_triangle]);
+		glBindBuffer(GL_ARRAY_BUFFER, renderer->vbo[rendermode_triangle]);
+
+		glEnableVertexAttribArray(0);
+		u32 numVertexElements = 3;
+		u32 stride            = sizeof(Vertex);
+
+		glVertexAttribPointer(0, numVertexElements, GL_FLOAT,
+		                      GL_FALSE, stride, (GLvoid *)0);
+		glBindBuffer(GL_ARRAY_BUFFER, 0);
+		glBindVertexArray(0);
+	}
 
 	/* Unbind */
-	glBindBuffer(GL_ARRAY_BUFFER, 0);
-	glBindVertexArray(0);
 	GL_CHECK_ERROR();
 
 	// TODO(doyle): Lazy allocate render group capacity
@@ -167,6 +182,8 @@ void asteroid_gameUpdateAndRender(GameState *state, Memory *memory,
 		initAssetManager(state);
 		initRenderer(state, windowSize);
 
+		state->pixelsPerMeter = 70.0f;
+
 		{ // Init ship entity
 			Entity *ship    = &state->entityList[state->entityIndex++];
 			ship->id        = 0;
@@ -183,6 +200,7 @@ void asteroid_gameUpdateAndRender(GameState *state, Memory *memory,
 		state->camera.pos = V2(0, 0);
 		state->camera.size = state->renderer.size;
 
+
 		state->init = TRUE;
 	}
 	{
@@ -217,25 +235,75 @@ void asteroid_gameUpdateAndRender(GameState *state, Memory *memory,
 
 		if (entity->type == entitytype_ship) {
 
-			{ // Parse input
-				if (getKeyStatus(&state->input.keys[keycode_up],
-				                 readkeytype_repeat, 0.0f, dt))
-				{
-					entity->pos.y += 10.0f;
-				}
 
-				if (getKeyStatus(&state->input.keys[keycode_down],
+			v2 acceleration = {0};
-				                 readkeytype_repeat, 0.0f, dt))
+			if (getKeyStatus(&state->input.keys[keycode_up], readkeytype_repeat,
-				{
+			                 0.0f, dt))
-					entity->pos.y -= 10.0f;
+			{
-				}
+				acceleration.y = 1.0f;
 			}
 
+			if (getKeyStatus(&state->input.keys[keycode_down],
+			                 readkeytype_repeat, 0.0f, dt))
+			{
+				acceleration.y = -1.0f;
+			}
+
+			if (getKeyStatus(&state->input.keys[keycode_left],
+			                 readkeytype_repeat, 0.0f, dt))
+			{
+				acceleration.x = -1.0f;
+			}
+
+			if (getKeyStatus(&state->input.keys[keycode_right],
+			                 readkeytype_repeat, 0.0f, dt))
+			{
+				acceleration.x = 1.0f;
+			}
+
+			if (acceleration.x != 0.0f && acceleration.y != 0.0f)
+			{
+				// NOTE(doyle): Cheese it and pre-compute the vector for
+				// diagonal using pythagoras theorem on a unit triangle 1^2
+				// + 1^2 = c^2
+				acceleration = v2_scale(acceleration, 0.70710678118f);
+			}
+
+			/*
+			    Assuming acceleration A over t time, then integrate twice to get
+
+			    newVelocity = a*t + oldVelocity
+			    newPos = (a*t^2)/2 + oldVelocity*t + oldPos
+			*/
+
+			acceleration = v2_scale(acceleration, state->pixelsPerMeter * 25);
+
+			v2 oldVelocity = entity->velocity;
+			v2 resistance = v2_scale(oldVelocity, 4.0f);
+			acceleration = v2_sub(acceleration, resistance);
+
+			entity->velocity = v2_add(v2_scale(acceleration, dt), oldVelocity);
+
+			v2 halfAcceleration = v2_scale(acceleration, 0.5f);
+			v2 halfAccelerationDtSquared =
+			    v2_scale(halfAcceleration, (SQUARED(dt)));
+			v2 oldVelocityDt = v2_scale(oldVelocity, dt);
+			v2 oldPos = entity->pos;
+			entity->pos      = v2_add(
+			    v2_add(halfAccelerationDtSquared, oldVelocityDt), oldPos);
 		}
 
 		renderer_entity(&state->renderer, state->camera, entity, V2(0, 0), 0,
-		                V4(1.0f, 1.0f, 1.0f, 1.0f));
+		                 V4(0.0f, 1.0f, 1.0f, 1.0f));
 	}
 
+	RenderTex nullRenderTex = renderer_createNullRenderTex(&state->assetManager);
+	TrianglePoints triangle = {0};
+	triangle.points[0] = V2(100, 200);
+	triangle.points[2] = V2(100, 100);
+	triangle.points[1] = V2(200, 100);
+	renderer_triangle(&state->renderer, state->camera, triangle, V2(0, 0), 0,
+	                  nullRenderTex, V4(1, 1, 1, 1));
+
 	renderer_renderGroups(&state->renderer);
 }

src/Renderer.c

@@ -10,8 +10,19 @@
 
 #define RENDER_BOUNDING_BOX FALSE
 
+typedef struct RenderQuad
+{
+	Vertex vertex[4];
+} RenderQuad_;
+
+typedef struct RenderTriangle
+{
+	Vertex vertex[3];
+} RenderTriangle_;
+
 INTERNAL void addVertexToRenderGroup(Renderer *renderer, Texture *tex, v4 color,
-                                     Vertex *vertexList, i32 numVertexes)
+                                     Vertex *vertexList, i32 numVertexes,
+                                     enum RenderMode targetRenderMode)
 {
 
 #ifdef DENGINE_DEBUG
@@ -32,7 +43,7 @@ INTERNAL void addVertexToRenderGroup(Renderer *renderer, Texture *tex, v4 color,
 			/* If the textures match and have the same color modulation, we can
 			 * add these vertices to the current group */
 			if (group->tex->id == tex->id &&
-			    v4_equals(group->color, color))
+			    v4_equals(group->color, color) && group->mode == targetRenderMode)
 			{
 				groupIsValid = TRUE;
 			}
@@ -46,6 +57,7 @@ INTERNAL void addVertexToRenderGroup(Renderer *renderer, Texture *tex, v4 color,
 			group->vertexIndex++;
 			group->tex   = tex;
 			group->color = color;
+			group->mode  = targetRenderMode;
 
 #ifdef DENGINE_DEBUG
 			debug_countIncrement(debugcount_renderGroups);
@@ -90,37 +102,6 @@ INTERNAL void addVertexToRenderGroup(Renderer *renderer, Texture *tex, v4 color,
 	}
 }
 
-INTERNAL inline void addRenderQuadToRenderGroup(Renderer *renderer,
-                                                RenderQuad_ quad,
-                                                Texture *tex, v4 color)
-{
-	/*
-	   NOTE(doyle): Entity rendering is always done in two pairs of
-	   triangles, i.e. quad. To batch render quads as a triangle strip, we
-	   need to create zero-area triangles which OGL will omit from
-	   rendering. Render groups are initialised with 1 degenerate vertex and
-	   then the first two vertexes sent to the render group are the same to
-	   form 1 zero-area triangle strip.
-
-	   A degenerate vertex has to be copied from the last vertex in the
-	   rendering quad, to repeat this process as more entities are
-	   renderered.
-
-	   Alternative implementation is recognising if the rendered
-	   entity is the first in its render group, then we don't need to init
-	   a degenerate vertex, and only at the end of its vertex list. But on
-	   subsequent renders, we need a degenerate vertex at the front to
-	   create the zero-area triangle strip.
-
-	   The first has been chosen for simplicity of code, at the cost of
-	   1 degenerate vertex at the start of each render group.
-   */
-	Vertex vertexList[6] = {quad.vertex[0], quad.vertex[0], quad.vertex[1],
-	                        quad.vertex[2], quad.vertex[3], quad.vertex[3]};
-	addVertexToRenderGroup(renderer, tex, color, vertexList,
-	                       ARRAY_COUNT(vertexList));
-};
-
 INTERNAL inline void flipTexCoord(v4 *texCoords, b32 flipX, b32 flipY)
 {
 	if (flipX)
@@ -138,24 +119,19 @@ INTERNAL inline void flipTexCoord(v4 *texCoords, b32 flipX, b32 flipY)
 	}
 }
 
-INTERNAL void updateBufferObject(Renderer *const renderer,
+INTERNAL void bufferRenderGroupToGL(Renderer *renderer, RenderGroup *group)
-                                 const Vertex *const vertexList,
-                                 const i32 numVertex)
 {
+	Vertex *vertexList = group->vertexList;
+	i32 numVertex = group->vertexIndex;
+
 	// TODO(doyle): We assume that vbo and vao are assigned
 	renderer->numVertexesInVbo = numVertex;
-
+	glBindBuffer(GL_ARRAY_BUFFER, renderer->vbo[group->mode]);
-	glBindBuffer(GL_ARRAY_BUFFER, renderer->vbo);
 	glBufferData(GL_ARRAY_BUFFER, numVertex * sizeof(Vertex), vertexList,
 	             GL_STREAM_DRAW);
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 }
 
-INTERNAL void bufferRenderGroupToGL(Renderer *renderer, RenderGroup *group)
-{
-	updateBufferObject(renderer, group->vertexList, group->vertexIndex);
-}
-
 INTERNAL RenderQuad_ createRenderQuad(Renderer *renderer, v2 pos, v2 size,
                                       v2 pivotPoint, f32 rotate,
                                       RenderTex renderTex)
@@ -237,6 +213,39 @@ INTERNAL RenderQuad_ createRenderQuad(Renderer *renderer, v2 pos, v2 size,
 	return result;
 }
 
+INTERNAL RenderTriangle_ createRenderTriangle(Renderer *renderer,
+                                              TrianglePoints triangle,
+                                              v2 pivotPoint, f32 rotate,
+                                              RenderTex renderTex)
+{
+	/* Convert texture coordinates to normalised texture coordinates */
+	v4 texRectNdc = renderTex.texRect;
+	if (renderTex.tex)
+	{
+		v2 texNdcFactor =
+		    V2(1.0f / renderTex.tex->width, 1.0f / renderTex.tex->height);
+		texRectNdc.e[0] *= texNdcFactor.w;
+		texRectNdc.e[1] *= texNdcFactor.h;
+		texRectNdc.e[2] *= texNdcFactor.w;
+		texRectNdc.e[3] *= texNdcFactor.h;
+	}
+	
+	RenderTriangle_ result = {0};
+
+	result.vertex[0].pos       = triangle.points[0];
+	result.vertex[0].texCoord  = V2(texRectNdc.x, texRectNdc.w);
+
+	result.vertex[1].pos       = triangle.points[1];
+	result.vertex[1].texCoord  = V2(texRectNdc.x, texRectNdc.y);
+
+	result.vertex[2].pos       = triangle.points[2];
+	result.vertex[2].texCoord  = V2(texRectNdc.z, texRectNdc.w);
+
+	if (rotate == 0) return result;
+
+	return result;
+}
+
 INTERNAL inline RenderQuad_
 createDefaultTexQuad(Renderer *renderer, RenderTex renderTex)
 {
@@ -248,6 +257,7 @@ createDefaultTexQuad(Renderer *renderer, RenderTex renderTex)
 
 INTERNAL void renderGLBufferedData(Renderer *renderer, RenderGroup *renderGroup)
 {
+	ASSERT(renderGroup->mode < rendermode_invalid);
 	/* Load transformation matrix */
 	shader_use(renderer->shader);
 	GL_CHECK_ERROR();
@@ -255,10 +265,11 @@ INTERNAL void renderGLBufferedData(Renderer *renderer, RenderGroup *renderGroup)
 	/* Set color modulation value */
 	shader_uniformSetVec4f(renderer->shader, "spriteColor",
 	                       renderGroup->color);
+	GL_CHECK_ERROR();
 
     /* Send draw calls */
 #if RENDER_BOUNDING_BOX
-	glBindVertexArray(renderer->vao);
+	glBindVertexArray(renderer->vao[renderGroup->mode]);
 	glDrawArrays(GL_TRIANGLE_STRIP, 0, renderer->numVertexesInVbo);
 	glBindVertexArray(0);
 #endif
@@ -271,8 +282,9 @@ INTERNAL void renderGLBufferedData(Renderer *renderer, RenderGroup *renderGroup)
 		shader_uniformSet1i(renderer->shader, "tex", 0);
 	}
 
-	glBindVertexArray(renderer->vao);
+	glBindVertexArray(renderer->vao[renderGroup->mode]);
 	glDrawArrays(GL_TRIANGLE_STRIP, 0, renderer->numVertexesInVbo);
+	GL_CHECK_ERROR();
 
 #ifdef DENGINE_DEBUG
 	debug_countIncrement(debugcount_drawArrays);
@@ -298,7 +310,56 @@ void renderer_rect(Renderer *const renderer, Rect camera, v2 pos, v2 size,
 	v2 posInCameraSpace = v2_sub(pos, camera.pos);
 	RenderQuad_ quad    = createRenderQuad(renderer, posInCameraSpace, size,
 	                                    pivotPoint, rotate, renderTex);
-	addRenderQuadToRenderGroup(renderer, quad, renderTex.tex, color);
+
+	{ // addRenderQuadToRenderGroup
+		/*
+		   NOTE(doyle): Entity rendering is always done in two pairs of
+		   triangles, i.e. quad. To batch render quads as a triangle strip, we
+		   need to create zero-area triangles which OGL will omit from
+		   rendering. Render groups are initialised with 1 degenerate vertex and
+		   then the first two vertexes sent to the render group are the same to
+		   form 1 zero-area triangle strip.
+
+		   A degenerate vertex has to be copied from the last vertex in the
+		   rendering quad, to repeat this process as more entities are
+		   renderered.
+
+		   Alternative implementation is recognising if the rendered
+		   entity is the first in its render group, then we don't need to init
+		   a degenerate vertex, and only at the end of its vertex list. But on
+		   subsequent renders, we need a degenerate vertex at the front to
+		   create the zero-area triangle strip.
+
+		   The first has been chosen for simplicity of code, at the cost of
+		   1 degenerate vertex at the start of each render group.
+		   */
+		Vertex vertexList[6] = {quad.vertex[0], quad.vertex[0], quad.vertex[1],
+		                        quad.vertex[2], quad.vertex[3], quad.vertex[3]};
+		addVertexToRenderGroup(renderer, renderTex.tex, color, vertexList,
+		                       ARRAY_COUNT(vertexList), rendermode_quad);
+	}
+
+}
+
+void renderer_triangle(Renderer *const renderer, Rect camera,
+                       TrianglePoints triangle, v2 pivotPoint, f32 rotate,
+                       RenderTex renderTex, v4 color)
+{
+	TrianglePoints triangleInCamSpace = {0};
+	ASSERT(ARRAY_COUNT(triangle.points) ==
+	       ARRAY_COUNT(triangleInCamSpace.points));
+
+	for (i32 i = 0; i < ARRAY_COUNT(triangleInCamSpace.points); i++)
+	{
+		triangleInCamSpace.points[i] = v2_sub(triangle.points[i], camera.pos);
+	}
+
+	RenderTriangle_ renderTriangle = createRenderTriangle(
+	    renderer, triangleInCamSpace, pivotPoint, rotate, renderTex);
+
+	addVertexToRenderGroup(
+	    renderer, renderTex.tex, color, renderTriangle.vertex,
+	    ARRAY_COUNT(renderTriangle.vertex), rendermode_triangle);
 }
 
 void renderer_string(Renderer *const renderer, MemoryArena_ *arena, Rect camera,
@@ -361,7 +422,7 @@ void renderer_string(Renderer *const renderer, MemoryArena_ *arena, Rect camera,
 		}
 
 		addVertexToRenderGroup(renderer, tex, color, vertexList,
-		                       numVertexesToAlloc);
+		                       numVertexesToAlloc, rendermode_quad);
 		// TODO(doyle): Mem free
 		// PLATFORM_MEM_FREE(arena, vertexList,
 		//                  sizeof(Vertex) * numVertexesToAlloc);

src/dengine.c

@@ -233,7 +233,7 @@ i32 main(void)
 			char textBuffer[256];
 			snprintf(textBuffer, ARRAY_COUNT(textBuffer),
 			         "Dengine | %f ms/f | %f fps | Entity Count: %d",
-			         msPerFrame, framesPerSecond, 0);
+			         msPerFrame, framesPerSecond, gameState.entityIndex);
 
 			glfwSetWindowTitle(window, textBuffer);
 			titleUpdateFrequencyInSeconds = 0.5f;

src/include/Dengine/Asteroid.h

@@ -13,6 +13,7 @@ typedef struct GameState {
 
 	Entity entityList[1024];
 	i32 entityIndex;
+	f32 pixelsPerMeter;
 
 	Rect camera;
 

src/include/Dengine/Entity.h

@@ -39,8 +39,8 @@ typedef struct Entity
 	i32 childIds[8];
 	i32 numChilds;
 
-	v2 pos;  // Position
+	v2 pos;
-	v2 dPos; // Velocity
+	v2 velocity;
 	v2 hitbox;
 	v2 size;
 

src/include/Dengine/Renderer.h

@@ -24,25 +24,36 @@ typedef struct RenderTex
 	v4 texRect;
 } RenderTex;
 
-typedef struct RenderQuad
+typedef struct TrianglePoints {
-{
+	v2 points[3];
-	Vertex vertex[4];
+} TrianglePoints;
-} RenderQuad_;
 
 typedef struct RenderGroup
 {
+	enum RenderMode mode;
 	Texture *tex;
 	v4 color;
 
 	Vertex *vertexList;
 	i32 vertexIndex;
+
 } RenderGroup;
 
+enum RenderMode
+{
+	rendermode_quad,
+	rendermode_triangle,
+	rendermode_count,
+	rendermode_invalid,
+};
+
 typedef struct Renderer
 {
 	Shader *shader;
-	u32 vao;
+
-	u32 vbo;
+	u32 vao[rendermode_count];
+	u32 vbo[rendermode_count];
+
 	i32 numVertexesInVbo;
 	v2 vertexNdcFactor;
 	v2 size;
@@ -52,7 +63,8 @@ typedef struct Renderer
 } Renderer;
 
 // TODO(doyle): Use z-index occluding for rendering
-RenderTex renderer_createNullRenderTex(AssetManager *const assetManager);
+RenderTex
+renderer_createNullRenderTex(AssetManager *const assetManager);
 
 // TODO(doyle): Clean up lines
 // Renderer::~Renderer() { glDeleteVertexArrays(1, &this->quadVAO); }
@@ -68,6 +80,10 @@ inline void renderer_staticRect(Renderer *const renderer, v2 pos, v2 size,
 	              renderTex, color);
 }
 
+void renderer_triangle(Renderer *const renderer, Rect camera,
+                       TrianglePoints triangle, v2 pivotPoint, f32 rotate,
+                       RenderTex renderTex, v4 color);
+
 void renderer_string(Renderer *const renderer, MemoryArena_ *arena,
                      Rect camera, Font *const font,
                      const char *const string, v2 pos, v2 pivotPoint,