diff --git a/examples/simple.c b/examples/simple.c index a06e7cc6..c789d1af 100644 --- a/examples/simple.c +++ b/examples/simple.c @@ -27,9 +27,40 @@ #include #include +#include "linmath.h" + #include #include +static const struct +{ + float x, y; + float r, g, b; +} vertices[3] = +{ + { -0.6f, -0.4f, 1.f, 0.f, 0.f }, + { 0.6f, -0.4f, 0.f, 1.f, 0.f }, + { 0.f, 0.6f, 0.f, 0.f, 1.f } +}; + +static const char* vertex_shader_text = +"uniform mat4 MVP;\n" +"attribute vec3 vCol;\n" +"attribute vec2 vPos;\n" +"varying vec3 color;\n" +"void main()\n" +"{\n" +" gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n" +" color = vCol;\n" +"}\n"; + +static const char* fragment_shader_text = +"varying vec3 color;\n" +"void main()\n" +"{\n" +" gl_FragColor = vec4(color, 1.0);\n" +"}\n"; + static void error_callback(int error, const char* description) { fprintf(stderr, "Error: %s\n", description); @@ -44,12 +75,17 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action, int main(void) { GLFWwindow* window; + GLuint vertex_buffer, vertex_shader, fragment_shader, program; + GLint mvp_location, vpos_location, vcol_location; glfwSetErrorCallback(error_callback); if (!glfwInit()) exit(EXIT_FAILURE); + glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2); + glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0); + window = glfwCreateWindow(640, 480, "Simple example", NULL, NULL); if (!window) { @@ -57,16 +93,47 @@ int main(void) exit(EXIT_FAILURE); } + glfwSetKeyCallback(window, key_callback); + glfwMakeContextCurrent(window); gladLoadGLLoader((GLADloadproc) glfwGetProcAddress); glfwSwapInterval(1); - glfwSetKeyCallback(window, key_callback); + // NOTE: OpenGL error checks have been omitted for brevity + + glGenBuffers(1, &vertex_buffer); + glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer); + glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); + + vertex_shader = glCreateShader(GL_VERTEX_SHADER); + glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL); + glCompileShader(vertex_shader); + + fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); + glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL); + glCompileShader(fragment_shader); + + program = glCreateProgram(); + glAttachShader(program, vertex_shader); + glAttachShader(program, fragment_shader); + glLinkProgram(program); + + mvp_location = glGetUniformLocation(program, "MVP"); + vpos_location = glGetAttribLocation(program, "vPos"); + vcol_location = glGetAttribLocation(program, "vCol"); + + glEnableVertexAttribArray(vpos_location); + glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE, + sizeof(float) * 5, (void*) 0); + glEnableVertexAttribArray(vcol_location); + glVertexAttribPointer(vcol_location, 3, GL_FLOAT, GL_FALSE, + sizeof(float) * 5, (void*) (sizeof(float) * 2)); while (!glfwWindowShouldClose(window)) { float ratio; int width, height; + mat4x4 m, p, mvp; glfwGetFramebufferSize(window, &width, &height); ratio = width / (float) height; @@ -74,22 +141,14 @@ int main(void) glViewport(0, 0, width, height); glClear(GL_COLOR_BUFFER_BIT); - glMatrixMode(GL_PROJECTION); - glLoadIdentity(); - glOrtho(-ratio, ratio, -1.f, 1.f, 1.f, -1.f); - glMatrixMode(GL_MODELVIEW); + mat4x4_identity(m); + mat4x4_rotate_Z(m, m, (float) glfwGetTime()); + mat4x4_ortho(p, -ratio, ratio, -1.f, 1.f, 1.f, -1.f); + mat4x4_mul(mvp, p, m); - glLoadIdentity(); - glRotatef((float) glfwGetTime() * 50.f, 0.f, 0.f, 1.f); - - glBegin(GL_TRIANGLES); - glColor3f(1.f, 0.f, 0.f); - glVertex3f(-0.6f, -0.4f, 0.f); - glColor3f(0.f, 1.f, 0.f); - glVertex3f(0.6f, -0.4f, 0.f); - glColor3f(0.f, 0.f, 1.f); - glVertex3f(0.f, 0.6f, 0.f); - glEnd(); + glUseProgram(program); + glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) mvp); + glDrawArrays(GL_TRIANGLES, 0, 3); glfwSwapBuffers(window); glfwPollEvents();