1 files changed, 190 insertions, 0 deletions
diff --git a/tests/gl/sdl_ogl.c b/tests/gl/sdl_ogl.c
new file mode 100644
index 00000000..829213d8
--- /dev/null
+++ b/tests/gl/sdl_ogl.c
@@ -0,0 +1,190 @@
+/*******************************************************************
+ *                                                                 *
+ *                        Using SDL With OpenGL                    *
+ *                                                                 *
+ *                    Tutorial by Kyle Foley (sdw)                 *
+ *                                                                 *
+ * http://gpwiki.org/index.php/SDL:Tutorials:Using_SDL_with_OpenGL *
+ *                                                                 *
+ *******************************************************************/
+
+/*
+  Combined with opengl.org tutorial #2,
+      http://www.opengl.org/wiki/Tutorial2:_VAOs,_VBOs,_Vertex_and_Fragment_Shaders_%28C_/_SDL%29
+*/
+
+#include "SDL/SDL.h"
+#include "SDL/SDL_opengl.h"
+
+#include <stdio.h>
+
+char* filetobuf(char *file)
+{
+  FILE *fptr;
+  long length;
+  char *buf;
+
+  fptr = fopen(file, "r"); /* Open file for reading */
+  if (!fptr) /* Return NULL on failure */
+      return NULL;
+  fseek(fptr, 0, SEEK_END); /* Seek to the end of the file */
+  length = ftell(fptr); /* Find out how many bytes into the file we are */
+  buf = (char*)malloc(length+1); /* Allocate a buffer for the entire length of the file and a null terminator */
+  fseek(fptr, 0, SEEK_SET); /* Go back to the beginning of the file */
+  fread(buf, length, 1, fptr); /* Read the contents of the file in to the buffer */
+  fclose(fptr); /* Close the file */
+  buf[length] = 0; /* Null terminator */
+
+  return buf; /* Return the buffer */
+}
+
+void drawscene()
+{
+  int i; /* Simple iterator */
+  GLuint vao, vbo[2]; /* Create handles for our Vertex Array Object and two Vertex Buffer Objects */
+
+  /* We're going to create a simple diamond made from lines */
+  const GLfloat diamond[4][2] = {
+  {  0.0,  1.0  }, /* Top point */
+  {  1.0,  0.0  }, /* Right point */
+  {  0.0, -1.0  }, /* Bottom point */
+  { -1.0,  0.0  } }; /* Left point */
+
+  const GLfloat colors[4][3] = {
+  {  1.0,  0.0,  0.0  }, /* Red */
+  {  0.0,  1.0,  0.0  }, /* Green */
+  {  0.0,  0.0,  1.0  }, /* Blue */
+  {  1.0,  1.0,  1.0  } }; /* White */
+
+  /* These pointers will receive the contents of our shader source code files */
+  GLchar *vertexsource, *fragmentsource;
+
+  /* These are handles used to reference the shaders */
+  GLuint vertexshader, fragmentshader;
+
+  /* This is a handle to the shader program */
+  GLuint shaderprogram;
+
+  /* Allocate and assign a Vertex Array Object to our handle */
+  glGenVertexArrays(1, &vao);
+
+  /* Bind our Vertex Array Object as the current used object */
+  glBindVertexArray(vao);
+
+  /* Allocate and assign two Vertex Buffer Objects to our handle */
+  glGenBuffers(2, vbo);
+
+  /* Bind our first VBO as being the active buffer and storing vertex attributes (coordinates) */
+  glBindBuffer(GL_ARRAY_BUFFER, vbo[0]);
+
+  /* Copy the vertex data from diamond to our buffer */
+  /* 8 * sizeof(GLfloat) is the size of the diamond array, since it contains 8 GLfloat values */
+  glBufferData(GL_ARRAY_BUFFER, 8 * sizeof(GLfloat), diamond, GL_STATIC_DRAW);
+
+  /* Specify that our coordinate data is going into attribute index 0, and contains two floats per vertex */
+  glVertexAttribPointer((GLuint)0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+
+  /* Enable attribute index 0 as being used */
+  glEnableVertexAttribArray(0);
+
+  /* Bind our second VBO as being the active buffer and storing vertex attributes (colors) */
+  glBindBuffer(GL_ARRAY_BUFFER, vbo[1]);
+
+  /* Copy the color data from colors to our buffer */
+  /* 12 * sizeof(GLfloat) is the size of the colors array, since it contains 12 GLfloat values */
+  glBufferData(GL_ARRAY_BUFFER, 12 * sizeof(GLfloat), colors, GL_STATIC_DRAW);
+
+  /* Specify that our color data is going into attribute index 1, and contains three floats per vertex */
+  glVertexAttribPointer((GLuint)1, 3, GL_FLOAT, GL_FALSE, 0, 0);
+
+  /* Enable attribute index 1 as being used */
+  glEnableVertexAttribArray(1);
+
+  /* Read our shaders into the appropriate buffers */
+  vertexsource = filetobuf("tutorial2.vert");
+  fragmentsource = filetobuf("tutorial2.frag");
+
+  /* Assign our handles a "name" to new shader objects */
+  vertexshader = glCreateShader(GL_VERTEX_SHADER);
+  fragmentshader = glCreateShader(GL_FRAGMENT_SHADER);
+
+  /* Associate the source code buffers with each handle */
+  glShaderSource(vertexshader, 1, (const GLchar**)&vertexsource, 0);
+  glShaderSource(fragmentshader, 1, (const GLchar**)&fragmentsource, 0);
+
+  /* Compile our shader objects */
+  glCompileShader(vertexshader);
+  glCompileShader(fragmentshader);
+
+  /* Assign our program handle a "name" */
+  shaderprogram = glCreateProgram();
+
+  /* Attach our shaders to our program */
+  glAttachShader(shaderprogram, vertexshader);
+  glAttachShader(shaderprogram, fragmentshader);
+
+  /* Bind attribute index 0 (coordinates) to in_Position and attribute index 1 (color) to in_Color */
+  glBindAttribLocation(shaderprogram, 0, "in_Position");
+  glBindAttribLocation(shaderprogram, 1, "in_Color");
+
+  /* Link our program, and set it as being actively used */
+  glLinkProgram(shaderprogram);
+  glUseProgram(shaderprogram);
+
+  /* Loop our display increasing the number of shown vertexes each time.
+   * Start with 2 vertexes (a line) and increase to 3 (a triangle) and 4 (a diamond) */
+  for (i=4; i <= 4; i++)
+  {
+    /* Make our background black */
+    glClearColor(0.0, 0.0, 0.0, 1.0);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    /* Invoke glDrawArrays telling that our data is a line loop and we want to draw 2-4 vertexes */
+    glDrawArrays(GL_LINE_LOOP, 0, i);
+
+    /* Swap our buffers to make our changes visible */
+    SDL_GL_SwapBuffers();
+
+    /* Sleep for 2 seconds */
+    SDL_Delay(2000);
+  }
+
+  /* Cleanup all the things we bound and allocated */
+  glUseProgram(0);
+  glDisableVertexAttribArray(0);
+  glDisableVertexAttribArray(1);
+  glDetachShader(shaderprogram, vertexshader);
+  glDetachShader(shaderprogram, fragmentshader);
+  glDeleteProgram(shaderprogram);
+  glDeleteShader(vertexshader);
+  glDeleteShader(fragmentshader);
+  glDeleteBuffers(2, vbo);
+  glDeleteVertexArrays(1, &vao);
+  free(vertexsource);
+  free(fragmentsource);
+}
+
+int main(int argc, char *argv[])
+{
+  SDL_Surface *screen;
+
+  // Slightly different SDL initialization
+  if ( SDL_Init(SDL_INIT_VIDEO) != 0 ) {
+      printf("Unable to initialize SDL: %s\n", SDL_GetError());
+      return 1;
+  }
+
+  SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ); // *new*
+
+  screen = SDL_SetVideoMode( 512, 384, 32, SDL_OPENGL); // *changed*
+  if ( !screen ) {
+    printf("Unable to set video mode: %s\n", SDL_GetError());
+    return 1;
+  }
+  
+  drawscene();
+   
+  SDL_Quit();
+    
+  return 0;
+}