Use VBO indexing.

CMakeLists.txt

@@ -46,9 +46,11 @@ include_directories(
 
 set(SRCS
 	"src/camera.cpp"
+	"src/cube.cpp"
 	"src/input.cpp"
 	"src/main.cpp"
-	"src/shaders.cpp")
+	"src/shaders.cpp"
+	"src/simulation.cpp")
 
 # Define C++ compiler flags
 set(CMAKE_CXX_FLAGS "-std=c++11 -Wall -Wextra -Wpedantic -Wfatal-errors -Werror -pedantic-errors -fno-elide-constructors")

src/cube.cpp

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2018 Ortega Froysa, Nicolás <nortega@themusicinnoise.net> All rights reserved.
+ * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ *
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ *
+ * 3. This notice may not be removed or altered from any source
+ *    distribution.
+ */
+
+#include "cube.hpp"
+
+#include <cstdlib>
+#include <ctime>
+
+cube::cube() {
+	glGenBuffers(1, &vbuffer);
+	glBindBuffer(GL_ARRAY_BUFFER, vbuffer);
+	glBufferData(GL_ARRAY_BUFFER,
+			vertices.size() * sizeof(GLfloat),
+			&vertices[0], GL_STATIC_DRAW);
+
+	glGenBuffers(1, &ibuffer);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuffer);
+	glBufferData(GL_ELEMENT_ARRAY_BUFFER,
+			indices.size() * sizeof(GLuint),
+			&indices[0], GL_STATIC_DRAW);
+
+	srand(static_cast<unsigned int>(time(0)));
+	for(size_t i = 0; i < vertices.size(); i += 3)
+	{
+		colors.push_back(static_cast<float>(rand()) /
+				static_cast<float>(RAND_MAX));
+		color_ascending.push_back(rand() % 2 ? true : false);
+	}
+
+	glGenBuffers(1, &cbuffer);
+	glBindBuffer(GL_ARRAY_BUFFER, cbuffer);
+	glBufferData(GL_ARRAY_BUFFER,
+			colors.size() * sizeof(GLfloat),
+			&colors[0], GL_STATIC_DRAW);
+}
+
+cube::~cube() {
+	glDeleteBuffers(1, &vbuffer);
+	glDeleteBuffers(1, &ibuffer);
+	glDeleteBuffers(1, &cbuffer);
+}
+
+void cube::render() {
+	shift_colors();
+	// setup vertex buffer
+	glEnableVertexAttribArray(0);
+	glBindBuffer(GL_ARRAY_BUFFER, vbuffer);
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
+
+	glEnableVertexAttribArray(1);
+	glBindBuffer(GL_ARRAY_BUFFER, cbuffer);
+	glBufferData(GL_ARRAY_BUFFER,
+			colors.size() * sizeof(GLfloat),
+			&colors[0], GL_STATIC_DRAW);
+	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
+
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuffer);
+	glDrawElements(GL_TRIANGLES, indices.size(),
+			GL_UNSIGNED_INT, nullptr);
+
+	glDisableVertexAttribArray(0);
+	glDisableVertexAttribArray(1);
+}
+
+void cube::shift_colors() {
+	for(size_t i = 0; i < colors.size(); ++i)
+	{
+		colors[i] += color_ascending[i] ? color_shift :
+			-color_shift;
+		if(colors[i] >= 1.0f)
+		{
+			colors[i] = 1.0f;
+			color_ascending[i] = false;
+		}
+		else if(colors[i] <= 0.0f)
+		{
+			colors[i] = 0.0f;
+			color_ascending[i] = true;
+		}
+	}
+}

src/cube.hpp

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2018 Ortega Froysa, Nicolás <nortega@themusicinnoise.net> All rights reserved.
+ * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ *
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ *
+ * 3. This notice may not be removed or altered from any source
+ *    distribution.
+ */
+
+#pragma once
+
+#include <vector>
+#include <GL/glew.h>
+#include <GL/gl.h>
+
+class cube {
+public:
+	cube();
+	~cube();
+
+	void render();
+
+private:
+	const float color_shift = 0.0001;
+	void shift_colors();
+
+	// OpenGL buffers
+	GLuint vbuffer;  // vertex buffer
+	GLuint ibuffer;  // index buffer
+	GLuint cbuffer;  // color buffer
+	// array of vertices
+	const std::vector<GLfloat> vertices = {
+		-1.0f, -1.0f, -1.0f,
+		-1.0f, -1.0f, 1.0f,
+		-1.0f, 1.0f, -1.0f,
+		-1.0f, 1.0f, 1.0f,
+		1.0f, -1.0f, -1.0f,
+		1.0f, -1.0f, 1.0f,
+		1.0f, 1.0f, -1.0f,
+		1.0f, 1.0f, 1.0f
+	};
+	// index array to make triangles
+	// NOTE: multiply the position x3 to get the position
+	// in the `vertices' array
+	const std::vector<GLuint> indices = {
+		0, 1, 2,
+		1, 3, 2,
+		2, 3, 7,
+		2, 7, 6,
+		2, 6, 4,
+		2, 4, 0,
+		0, 5, 1,
+		0, 4, 5,
+		1, 5, 3,
+		3, 5, 7,
+		6, 7, 5,
+		6, 5, 4
+	};
+
+	// color control
+	std::vector<GLfloat> colors;
+	std::vector<bool> color_ascending;
+};

src/globals.hpp

@@ -24,47 +24,12 @@
 
 #pragma once
 
-#include "input.hpp"
+#include <SDL2/SDL.h>
+#include <GL/gl.h>
+
 #define SCREEN_WIDTH 800
 #define SCREEN_HEIGHT 600
 
-extern input *in_sys;
+extern SDL_Window *window;
-
+extern GLuint program_id;
-static const GLfloat g_vertex_buffer_data[] = {
+extern GLuint matrix_id;
-	-1.0f,-1.0f,-1.0f,
-	-1.0f,-1.0f, 1.0f,
-	-1.0f, 1.0f, 1.0f,
-	1.0f, 1.0f,-1.0f,
-	-1.0f,-1.0f,-1.0f,
-	-1.0f, 1.0f,-1.0f,
-	1.0f,-1.0f, 1.0f,
-	-1.0f,-1.0f,-1.0f,
-	1.0f,-1.0f,-1.0f,
-	1.0f, 1.0f,-1.0f,
-	1.0f,-1.0f,-1.0f,
-	-1.0f,-1.0f,-1.0f,
-	-1.0f,-1.0f,-1.0f,
-	-1.0f, 1.0f, 1.0f,
-	-1.0f, 1.0f,-1.0f,
-	1.0f,-1.0f, 1.0f,
-	-1.0f,-1.0f, 1.0f,
-	-1.0f,-1.0f,-1.0f,
-	-1.0f, 1.0f, 1.0f,
-	-1.0f,-1.0f, 1.0f,
-	1.0f,-1.0f, 1.0f,
-	1.0f, 1.0f, 1.0f,
-	1.0f,-1.0f,-1.0f,
-	1.0f, 1.0f,-1.0f,
-	1.0f,-1.0f,-1.0f,
-	1.0f, 1.0f, 1.0f,
-	1.0f,-1.0f, 1.0f,
-	1.0f, 1.0f, 1.0f,
-	1.0f, 1.0f,-1.0f,
-	-1.0f, 1.0f,-1.0f,
-	1.0f, 1.0f, 1.0f,
-	-1.0f, 1.0f,-1.0f,
-	-1.0f, 1.0f, 1.0f,
-	1.0f, 1.0f, 1.0f,
-	-1.0f, 1.0f, 1.0f,
-	1.0f,-1.0f, 1.0f
-};

src/main.cpp

@@ -23,21 +23,18 @@
  */
 
 #include <iostream>
-#include <string>
-#include <cstdlib>
-#include <ctime>
 
 #include <SDL2/SDL.h>
 #include <GL/glew.h>
 #include <GL/gl.h>
-#include <glm/gtc/matrix_transform.hpp>
 
-#include "input.hpp"
 #include "globals.hpp"
 #include "shaders.hpp"
-#include "camera.hpp"
+#include "simulation.hpp"
 
-input *in_sys;
+SDL_Window *window;
+GLuint program_id;
+GLuint matrix_id;
 
 int main() {
 	if(SDL_Init(SDL_INIT_VIDEO) < 0)
@@ -50,7 +47,7 @@ int main() {
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
 			SDL_GL_CONTEXT_PROFILE_CORE);
-	SDL_Window *window = SDL_CreateWindow("OpenGL Tutorial",
+	window = SDL_CreateWindow("OpenGL Tutorial",
 			SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
 			SCREEN_WIDTH, SCREEN_HEIGHT,
 			SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN);
@@ -77,115 +74,22 @@ int main() {
 
 	glEnable(GL_DEPTH_TEST);
 	glDepthFunc(GL_LESS);
-
+	//glEnable(GL_CULL_FACE);
-	// vertex buffer
-	GLuint vbuffer;
-	glGenBuffers(1, &vbuffer);
-	glBindBuffer(GL_ARRAY_BUFFER, vbuffer);
-	glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data),
-			g_vertex_buffer_data, GL_STATIC_DRAW);
-
-	srand(static_cast<unsigned int>(time(0)));
-	GLfloat color_buffer_data[108];
-	// generate random colors every time
-	for(int i = 0; i < 108; ++i)
-	{
-		color_buffer_data[i] = static_cast<float>(rand()) /
-			static_cast<float>(RAND_MAX);
-	}
-	bool color_ascend[108];
-	for(int i = 0; i < 108; ++i)
-		color_ascend[i] = rand() % 2 ? true : false;
-
-	// color buffer
-	GLuint cbuffer;
-	glGenBuffers(1, &cbuffer);
-	glBindBuffer(GL_ARRAY_BUFFER, cbuffer);
-	glBufferData(GL_ARRAY_BUFFER, sizeof(color_buffer_data),
-			color_buffer_data, GL_STATIC_DRAW);
 
 	// load the shaders into a GLSL program that can be run
-	GLuint program_id = load_shaders("../shaders/vert_shader.glsl",
+	program_id = load_shaders("../shaders/vert_shader.glsl",
 			"../shaders/frag_shader.glsl");
-	GLuint matrix_id = glGetUniformLocation(program_id, "MVP");
+	matrix_id = glGetUniformLocation(program_id, "MVP");
 
 	// set the clear color to black
 	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 
-	in_sys = new input();
+	run();
-
-	camera cam;
-
-	while(true)
-	{
-		cam.update(in_sys);
-		// clear screen
-		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-
-		glUseProgram(program_id);
-
-		glm::mat4 mvp;
-		{
-			glm::mat4 proj = glm::perspective(glm::radians(45.0f),
-					static_cast<float>(SCREEN_WIDTH) / static_cast<float>(SCREEN_HEIGHT),
-					0.1f, 100.0f);
-
-			glm::mat4 view = glm::lookAt(
-					cam.get_pos(), // camera position
-					glm::vec3(0,0,0), // where the camera is looking
-					glm::vec3(0,1,0) // which way is vertically up
-					);
-			glm::mat4 mod = glm::mat4(1.0f); // identity matrix, object is at origin
-			mvp = proj * view * mod;
-		}
-
-		glUniformMatrix4fv(matrix_id, 1, GL_FALSE, &mvp[0][0]);
-
-		glEnableVertexAttribArray(0);
-		glBindBuffer(GL_ARRAY_BUFFER, vbuffer);
-		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
-
-		// change colors
-		for(int i = 0; i < 108; ++i)
-		{
-			const float color_delta = 0.0001f;
-			if(color_ascend[i])
-				color_buffer_data[i] += color_delta;
-			else
-				color_buffer_data[i] -= color_delta;
-
-			if(color_buffer_data[i] >= 1.0f)
-			{
-				color_buffer_data[i] = 1.0f;
-				color_ascend[i] = false;
-			}
-			else if(color_buffer_data[i] <= 0.0f)
-			{
-				color_buffer_data[i] = 0.0f;
-				color_ascend[i] = true;
-			}
-		}
-		glEnableVertexAttribArray(1);
-		glBindBuffer(GL_ARRAY_BUFFER, cbuffer);
-		glBufferData(GL_ARRAY_BUFFER, sizeof(color_buffer_data),
-				color_buffer_data, GL_STATIC_DRAW);
-		glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
-		glDrawArrays(GL_TRIANGLES, 0, 12*3);
-		glDisableVertexAttribArray(0);
-
-		SDL_GL_SwapWindow(window);
-
-		in_sys->sync_events();
-		if(in_sys->get_action("quit"))
-			break;
-	}
 
 #ifdef DEBUG
 	std::cout << "Shutting down..." << std::endl;
 #endif
 	glDeleteProgram(program_id);
-	glDeleteBuffers(1, &cbuffer);
-	glDeleteBuffers(1, &vbuffer);
 	SDL_GL_DeleteContext(glcontext);
 	SDL_DestroyWindow(window);
 	SDL_Quit();

src/simulation.cpp

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2018 Ortega Froysa, Nicolás <nortega@themusicinnoise.net> All rights reserved.
+ * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ *
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ *
+ * 3. This notice may not be removed or altered from any source
+ *    distribution.
+ */
+
+#include "simulation.hpp"
+
+#include <GL/glew.h>
+#include <GL/gl.h>
+#include <glm/gtc/matrix_transform.hpp>
+#include <SDL2/SDL.h>
+
+#include "globals.hpp"
+#include "input.hpp"
+#include "camera.hpp"
+#include "cube.hpp"
+
+void run() {
+	input in_sys;
+	camera cam;
+	cube box;
+
+	while(not in_sys.get_action("quit"))
+	{
+		cam.update(&in_sys);
+
+		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+		glUseProgram(program_id);
+
+		glm::mat4 mvp;
+		{
+			glm::mat4 proj = glm::perspective(glm::radians(45.0f),
+					static_cast<float>(SCREEN_WIDTH) / static_cast<float>(SCREEN_HEIGHT),
+					0.1f, 100.0f);
+
+			glm::mat4 view = glm::lookAt(
+					cam.get_pos(), // camera position
+					glm::vec3(0,0,0), // where the camera is looking
+					glm::vec3(0,1,0) // which way is vertically up
+					);
+			glm::mat4 mod = glm::mat4(1.0f); // identity matrix, object is at origin
+			mvp = proj * view * mod;
+
+		}
+		glUniformMatrix4fv(matrix_id, 1, GL_FALSE, &mvp[0][0]);
+
+		box.render();
+
+		SDL_GL_SwapWindow(window);
+
+		in_sys.sync_events();
+	}
+}

src/simulation.hpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2018 Ortega Froysa, Nicolás <nortega@themusicinnoise.net> All rights reserved.
+ * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ *
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ *
+ * 3. This notice may not be removed or altered from any source
+ *    distribution.
+ */
+
+#pragma once
+
+#include <GL/glew.h>
+
+void run();