Colored triangles with VAO and VBO

opengl-test-two/main.cpp

@@ -169,10 +169,6 @@ GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path
 int main(int argc, char* args[]) {
     GLFWwindow* window;
     GLuint tex_jpe;
-    GLuint tex_jpg;
-    GLuint tex_gif;
-    GLuint tex_png;
-    GLuint tex_bmp;
     int textw, texth;
     int timer = 0;
 
@@ -213,15 +209,56 @@ int main(int argc, char* args[]) {
     }
     // INIT
 
+
+    GLuint VertexArrayID;
+    glGenVertexArrays(1, &VertexArrayID);
+    glBindVertexArray(VertexArrayID);
+    // An array of 3 vectors which represents 3 vertices
+    static const GLfloat g_vertex_buffer_data[] = {
+       -1.0f, -1.0f, 0.0f,  // (bottom - left )  TRIANGLE 1
+        1.0f, -1.0f, 0.0f,  // (bottom - right)
+       -1.0f,  1.0f, 0.0f,  // (top    - left )
+        1.0f,  1.0f, 0.0f,  // (top    - right)  TRIANGLE 2
+        1.0f, -1.0f, 0.0f,  // (bottom - right)
+       -1.0f,  1.0f, 0.0f,  // (top    - left )
+    };
+    // One color for each vertex. They were generated randomly.
+    static const GLfloat g_color_buffer_data[] = {
+        0.583f,  0.771f,  0.014f,
+        0.609f,  0.115f,  0.436f,
+        0.327f,  0.483f,  0.844f,
+        0.822f,  0.569f,  0.201f,
+        0.435f,  0.602f,  0.223f,
+        0.310f,  0.747f,  0.185f,
+    };
+
+
+    // Identify our vertex buffer
+    GLuint vertexbuffer;
+    glGenBuffers(1, &vertexbuffer);
+    glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
+
+    // Identify our color buffer
+    GLuint colorbuffer;
+    glGenBuffers(1, &colorbuffer);
+    glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(g_color_buffer_data), g_color_buffer_data, GL_STATIC_DRAW);
+
+
+
+
+
+
+
     tex_jpe=LoadTexture("../img/tests/test.jpeg",&textw,&texth);
-    //tex_jpg=LoadTexture("../img/tests/test.jpg",&textw,&texth);
-    //tex_png=LoadTexture("../img/tests/test.png",&textw,&texth);
-    //tex_bmp=LoadTexture("../img/tests/test.bmp",&textw,&texth);
 
     GLuint programID = LoadShaders("trimap.vertexshader", "trimap.fragmentshader");
     printf("%d", programID);
-    GLint textureLocation = glGetUniformLocationARB(programID, "texture");
+    //GLint textureLocation = glGetUniformLocationARB(programID, "myTextureSampler");
-    glUniform1iARB(textureLocation, tex_jpe);
+    //glUniform1iARB(textureLocation, tex_jpe);
+
+
 
     // INIT END
     /* Loop until the user closes the window */
@@ -234,21 +271,35 @@ int main(int argc, char* args[]) {
 
         glUseProgram(programID);
 
-        // RENDER
+        // 1rst attribute buffer : vertices
-        /*if (timer<200)
+        glEnableVertexAttribArray(0);
-            DrawTexture(50,50,tex_jpe,textw,texth);
+        glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
-        else if (timer<400)
+        glVertexAttribPointer(
-            DrawTexture(50,50,tex_jpg,textw,texth);
+           0,                  // attribute 0. No particular reason for 0, but must match the layout in the shader.
-        else if (timer<600)
+           3,                  // size
-            DrawTexture(50,50,tex_png,textw,texth);
+           GL_FLOAT,           // type
-        else
+           GL_FALSE,           // normalized?
-            DrawTexture(50,50,tex_bmp,textw,texth);*/
+           0,                  // stride
-        glBegin(GL_QUADS);
+           (void*)0            // array buffer offset
-            glTexCoord2d(0.0,0.0); glVertex2f(-1, -1);
+        );
-            glTexCoord2d(1.0,0.0); glVertex2f(1, -1);
+        // 2nd attribute buffer : colors
-            glTexCoord2d(1.0,1.0); glVertex2f(1, 0);
+        glEnableVertexAttribArray(1);
-            glTexCoord2d(0.0,1.0); glVertex2f(-1, 0);
+        glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
-        glEnd();
+        glVertexAttribPointer(
+            1,                                // attribute. No particular reason for 1, but must match the layout in the shader.
+            3,                                // size
+            GL_FLOAT,                         // type
+            GL_FALSE,                         // normalized?
+            0,                                // stride
+            (void*)0                          // array buffer offset
+        );
+
+
+        // Draw the triangle !
+        glDrawArrays(GL_TRIANGLES, 0, 2*3); // 2*3 indices starting at 0 -> 2 triangles -> 1 square
+        glDisableVertexAttribArray(0);
+
+
 
         // RENDER END
         /* Swap front and back buffers */

opengl-test-two/opengl-test-two.depend

@@ -2,7 +2,7 @@
 1385320478 source:d:\owncloud\documents\programmierung\cpp\opengl-test-two\main.cpp
 	<iostream>
 
-1473070070 source:d:\owncloud\documents\programmierung\cpp\imanox-chroma-matting\opengl-test-two\main.cpp
+1473093222 source:d:\owncloud\documents\programmierung\cpp\imanox-chroma-matting\opengl-test-two\main.cpp
 	<GL/glew.h>
 	<GLFW/glfw3.h>
 	<SDL2/SDL.h>

opengl-test-two/trimap.fragmentshader

@@ -1,11 +1,8 @@
 #version 330 core
 
-uniform sampler2D texture;
+in vec3 fragmentColor;
-in vec2 vTexCoord;
+out vec3 color;
-out vec4 color;
 
 void main(){
-  //color = vec4(1f,0f,0f,1.0f);
+    color = fragmentColor;
-  vec2 tcoord=vec2(0.5f,0.5f);
-  color = vec4(texelFetch(texture, ivec2(vTexCoord), 0).rgb, 1);
 }

opengl-test-two/trimap.vertexshader

@@ -1,13 +1,11 @@
-#version 400
+#version 330 core
 
-in vec2 aVertex;
+layout(location = 0) in vec3 vertexPosition_modelspace;
-in vec2 aTexCoord;
+layout(location = 1) in vec3 vertexColor;
+out vec3 fragmentColor;
 
-out vec2 vTexCoord;
+void main(){
-out vec3 vNormal;
+    gl_Position.xyz = vertexPosition_modelspace;
-
+    gl_Position.w = 1.0;
-void main()
+    fragmentColor = vertexColor;
-{
-    vTexCoord   = aTexCoord;
-    gl_Position = vec3(aVertex, 1);
 }