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POOrthogonal projection, drawing square in OpenGL 2.0
 

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  1. POOrthogonal projection, drawing square in OpenGL 2.0
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    <p>I'm having troubles with proper drawing squares. I'm using glut and glew on Windows 7 x64.</p> <p>I can see only a black square(WALL in my app) in the right top corner.</p> <p>I'm trying to draw a labyrinth with squares.</p> <p>my source code without shaders:</p> <pre><code>#define GL_GLEXT_PROTOTYPES 1 #define FREEGLUT_LIB_PRAGMAS 1 #define FREEGLUT_STATIC 1 #include &lt;gl/glew.h&gt; #include &lt;gl/freeglut.h&gt; #include &lt;stdlib.h&gt; #include &lt;gl/glext.h&gt; #include "Shaders.h" #include &lt;iostream&gt; using namespace std; GLuint buf_v; GLuint buf_c; #define FOR(i,s,t) for(int i = (s); i &lt; (t);i++) int width = 480; int height = 800; const int N = 24; const int WALL = 9999; int map[N][N]; GLfloat arrQuad[12]; GLfloat color[] ={ 1.0,1.0,1.0,1.0}; Shaders shaders; Matrix w, v, p, wvp; void drawQuad(float x, float y, int isWALL = 9999){//from top left corner glUseProgram(shaders.program); glBindBuffer(GL_ARRAY_BUFFER, buf_v); GLvoid *buf = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY ); arrQuad[0] = x; arrQuad[1] = y; arrQuad[2] = x; arrQuad[3] = y + 1.0; arrQuad[4] = x + 1.0; arrQuad[5] = y; arrQuad[6] = x; arrQuad[7] = y + 1.0; arrQuad[8] = x + 1.0; arrQuad[9] = y; arrQuad[10] = x + 1.0; arrQuad[11] = y + 1.0; FOR(i,0,12){ arrQuad[i]*=(GLfloat)width; arrQuad[i]/=(GLfloat)N; } printf("%f, %f %f %f \n",arrQuad[3],arrQuad[4], arrQuad[10],arrQuad[11]); printf("%f, %f %f %f \n\n",arrQuad[0],arrQuad[1], arrQuad[8],arrQuad[9]); memcpy(buf, arrQuad, sizeof(arrQuad)); glUnmapBuffer(GL_ARRAY_BUFFER); if(isWALL == WALL){ color[0] = 1.0f; color[1] = 1.0f; color[2] = 1.0f; } else { color[0] = 0.0; color[1] = 0.0; color[2] = 0.0; } if(shaders.positionAttribute != -1) { glEnableVertexAttribArray(shaders.positionAttribute); glVertexAttribPointer(shaders.positionAttribute, 2, GL_FLOAT, GL_FALSE, 0, 0);; }else{ perror("err pos attr"); } if(shaders.colorUniform != -1) { glUniform4fv(shaders.colorUniform, 1, color); }else{ perror ("err col atr"); } GLfloat mat_wvp_16[16] = { wvp[0], wvp[1], wvp[2], wvp[3], wvp[4], wvp[5], wvp[6], wvp[7], wvp[8], wvp[9], wvp[10], wvp[11], wvp[12], wvp[13], wvp[14], wvp[15], }; if(shaders.mat_wvp != -1) { glUniformMatrix4fv(shaders.mat_wvp, 1, GL_FALSE, mat_wvp_16); }else{ //perror ("err mat atr"); } glBindBuffer(GL_ARRAY_BUFFER, buf_v); glDrawArrays(GL_TRIANGLES, 0, 6); glBindBuffer(GL_ARRAY_BUFFER, 0); } void reshape(int w, int h) { glViewport(0,0,(GLsizei)w,(GLsizei)h); } void init(){ shaders.HasGLSLSupport(); glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_COLOR_ARRAY); glGenBuffers(1, &amp;buf_v); glBindBuffer(GL_ARRAY_BUFFER, buf_v); glBufferData(GL_ARRAY_BUFFER, sizeof(arrQuad), arrQuad, GL_DYNAMIC_DRAW); glGenBuffers(1, &amp;buf_c); glBindBuffer(GL_ARRAY_BUFFER, buf_c); glBufferData(GL_ARRAY_BUFFER, sizeof(color), color, GL_DYNAMIC_DRAW); glBindBuffer(GL_ARRAY_BUFFER, 0); if(shaders.Init("vert.vs","frag.frg") != 0) perror("shader initialization error"); wvp.loadOrthoMatrix(0.0, width, 0, height, 0.0, 100.0); wvp = wvp * w; } void display() { glClear(GL_COLOR_BUFFER_BIT); FOR(i, 0, N) FOR(j, 0, N) { drawQuad(i, j, map[i][j]); } glutSwapBuffers(); } void timer(int i = 0) { glutPostRedisplay(); FOR(i, 0, N) FOR(j, 0, N) { if(rand() % 4 == 0) map[i][j] = WALL; else map[i][j] = -1; } display(); } int main(int argc, char **argv) { glutInit( &amp;argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA); glutInitWindowSize(width, height); glutCreateWindow("Hi, wave!"); glClearColor(1.0,1.0,1.0,1.0); glViewport(0,0,(GLfloat)width, (GLfloat)height); GLenum err = glewInit(); if (GLEW_OK != err) { cout &lt;&lt; "glewInit failed, aborting." &lt;&lt; endl; exit (1); } init(); glutTimerFunc(17,timer,0); glutDisplayFunc(display); glutReshapeFunc(reshape); glutMainLoop(); return 0; } </code></pre> <p>vert.vs</p> <pre><code>uniform mat4 u_wvp; attribute vec4 a_pos; void main () { gl_Position = (u_wvp * a_pos); } </code></pre> <p>frag.frg</p> <pre><code>precision mediump float; uniform vec4 u_color; void main(){ gl_FragColor = u_color; } </code></pre>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USSevenDays
    1. USSevenDays
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
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      1. POOrthogonal projection, drawing square in OpenGL 2.0
      1. This table or related slice is empty.
      1. VTDownMod
    2. VO
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      1. POOrthogonal projection, drawing square in OpenGL 2.0
      1. This table or related slice is empty.
      1. VTClose
    3. VO
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      1. POOrthogonal projection, drawing square in OpenGL 2.0
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      1. VTClose
    1. COShaders simply takes a value and sends it to video card. See update.
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      1. POOrthogonal projection, drawing square in OpenGL 2.0
      1. USSevenDays
    2. COWhere are your `#version` directives?
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      1. POOrthogonal projection, drawing square in OpenGL 2.0
      1. USgenpfault
    3. COWhen I set #version 110 nothing changes. GLSL must support 2.0 by default, I think.
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      1. POOrthogonal projection, drawing square in OpenGL 2.0
      1. USSevenDays
 

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