1 files changed, 62 insertions, 0 deletions
diff --git a/src/video/skybox.c b/src/video/skybox.c
new file mode 100644
index 0000000..ee01f38
--- /dev/null
+++ b/src/video/skybox.c
@@ -0,0 +1,62 @@
+#include "video/video.h"
+
+void enableSkyboxTexture(void) {
+  glEnable(GL_TEXTURE_2D);
+}
+
+void disableSkyboxTexture(void) {
+  glDisable(GL_TEXTURE_2D);
+}
+
+static void bindSkyboxTexture(int index) {
+  glBindTexture(GL_TEXTURE_2D, gScreen->textures[ TEX_SKYBOX + index ]);
+}
+
+void drawSkybox(int grid_size) {
+  /* 
+     matrices are: 
+     projection: perspective projection 
+     modelview: identity
+  */
+  
+  /* these are the values for y == up, x == front */
+  /* 
+  float sides[6][4][3] = {
+    { { 1, -1, -1 }, { 1, -1, 1 }, { 1, 1, 1 },  { 1, 1, -1 } }, // front
+    { { 1, 1, -1 }, { 1, 1, 1 }, { -1, 1, 1 }, { -1, 1, -1 } }, // top
+    { { -1, -1, -1 }, { 1, -1, -1 },  { 1, 1, -1 }, { -1, 1, -1 } }, // left
+    { { 1, -1, 1 }, { -1, -1, 1 }, { -1, 1, 1 }, { 1, 1, 1 } }, // right
+    { { -1, -1, -1 }, { 1, -1, -1 }, { 1, -1, 1 }, { -1, -1, 1 } }, // bottom
+    { { -1, -1, 1 }, { -1, -1, -1 }, { -1, 1, -1 }, { -1, 1, a1 } } // back
+  };
+  */
+
+  /* these values are for z == up, x == front */
+  float sides[6][4][3] = {
+    { { 1, 1, -1 }, { 1, -1, -1 }, { 1, -1, 1 },  { 1, 1, 1 } }, /* front */
+    { { 1, 1, 1 }, { -1, 1, 1 }, { -1, -1, 1 }, { 1, -1, 1 } }, /* top */
+    { { -1, 1, -1 }, { 1, 1, -1 },  { 1, 1, 1 }, { -1, 1, 1 } }, /* left */
+    { { 1, -1, -1 }, { -1, -1, -1 }, { -1, -1, 1 }, { 1, -1, 1 } }, /* right */
+    { { -1, 1, -1 }, { -1, -1, -1 }, { 1, -1, -1 }, { 1, 1, -1 } }, /* bottom */
+    { { -1, -1, -1 }, { -1, 1, -1 }, { -1, 1, 1 }, { -1, -1, 1 } } /* back */
+  };
+    
+  float uv[4][2] = { { 0, 0 }, { 1, 0 }, { 1, 1 }, { 0, 1 } };
+  int i, j;
+  float d = grid_size * 3;
+  
+  glEnable(GL_TEXTURE_2D);
+  glDepthMask(GL_FALSE);
+  glColor3f(1.0, 1.0, 1.0);
+  for(i = 0; i < 6; i++) {
+    bindSkyboxTexture(i);
+    glBegin(GL_QUADS);
+    for(j = 0; j < 4; j++) {
+      glTexCoord2fv( uv[j] );
+      glVertex3f( sides[i][j][0] * d, sides[i][j][1] * d, sides[i][j][2] * d );
+    }
+    glEnd();
+  }
+  glDisable(GL_TEXTURE_2D);
+  glDepthMask(GL_TRUE);
+}