Reviewed examples

examples/models/models_skybox.c

@@ -12,7 +12,8 @@
 #include "raylib.h"
 #include "rlgl.h"
 
-bool useHDR = false;
+// Generate cubemap (6 faces) from equirectangular (panorama) texture
+static TextureCubemap GenTextureCubemap(Shader shader, Texture2D panorama, int size, int format);
 
 int main(void)
 {
@@ -29,6 +30,8 @@ int main(void)
     // Load skybox model
     Mesh cube = GenMeshCube(1.0f, 1.0f, 1.0f);
     Model skybox = LoadModelFromMesh(cube);
+    
+    bool useHDR = false;
 
     // Load skybox shader and set required locations
     // NOTE: Some locations are automatically set at shader loading
@@ -62,7 +65,7 @@ int main(void)
         // NOTE 1: New texture is generated rendering to texture, shader calculates the sphere->cube coordinates mapping
         // NOTE 2: It seems on some Android devices WebGL, fbo does not properly support a FLOAT-based attachment,
         // despite texture can be successfully created.. so using PIXELFORMAT_UNCOMPRESSED_R8G8B8A8 instead of PIXELFORMAT_UNCOMPRESSED_R32G32B32A32
-        skybox.materials[0].maps[MATERIAL_MAP_CUBEMAP].texture = rlGenTextureCubemap(shdrCubemap, panorama, 1024, PIXELFORMAT_UNCOMPRESSED_R8G8B8A8);
+        skybox.materials[0].maps[MATERIAL_MAP_CUBEMAP].texture = GenTextureCubemap(shdrCubemap, panorama, 1024, PIXELFORMAT_UNCOMPRESSED_R8G8B8A8);
 
         UnloadTexture(panorama);    // Texture not required anymore, cubemap already generated
     }
@@ -102,7 +105,7 @@ int main(void)
                         Texture2D panorama = LoadTexture(droppedFiles[0]);
                         
                         // Generate cubemap from panorama texture
-                        skybox.materials[0].maps[MATERIAL_MAP_CUBEMAP].texture = rlGenTextureCubemap(shdrCubemap, panorama, 1024, PIXELFORMAT_UNCOMPRESSED_R8G8B8A8);
+                        skybox.materials[0].maps[MATERIAL_MAP_CUBEMAP].texture = GenTextureCubemap(shdrCubemap, panorama, 1024, PIXELFORMAT_UNCOMPRESSED_R8G8B8A8);
                         UnloadTexture(panorama);
                     }
                     else
@@ -162,3 +165,78 @@ int main(void)
 
     return 0;
 }
+
+// Generate cubemap texture from HDR texture
+static TextureCubemap GenTextureCubemap(Shader shader, Texture2D panorama, int size, int format)
+{
+    TextureCubemap cubemap = { 0 };
+
+    rlDisableBackfaceCulling();     // Disable backface culling to render inside the cube
+
+    // STEP 1: Setup framebuffer
+    //------------------------------------------------------------------------------------------
+    unsigned int rbo = rlLoadTextureDepth(size, size, true);
+    cubemap.id = rlLoadTextureCubemap(0, size, format);
+
+    unsigned int fbo = rlLoadFramebuffer(size, size);
+    rlFramebufferAttach(fbo, rbo, RL_ATTACHMENT_DEPTH, RL_ATTACHMENT_RENDERBUFFER, 0);
+    rlFramebufferAttach(fbo, cubemap.id, RL_ATTACHMENT_COLOR_CHANNEL0, RL_ATTACHMENT_CUBEMAP_POSITIVE_X, 0);
+
+    // Check if framebuffer is complete with attachments (valid)
+    if (rlFramebufferComplete(fbo)) TraceLog(LOG_INFO, "FBO: [ID %i] Framebuffer object created successfully", fbo);
+    //------------------------------------------------------------------------------------------
+
+    // STEP 2: Draw to framebuffer
+    //------------------------------------------------------------------------------------------
+    // NOTE: Shader is used to convert HDR equirectangular environment map to cubemap equivalent (6 faces)
+    rlEnableShader(shader.id);
+
+    // Define projection matrix and send it to shader
+    Matrix matFboProjection = MatrixPerspective(90.0*DEG2RAD, 1.0, RL_CULL_DISTANCE_NEAR, RL_CULL_DISTANCE_FAR);
+    rlSetUniformMatrix(shader.locs[SHADER_LOC_MATRIX_PROJECTION], matFboProjection);
+
+    // Define view matrix for every side of the cubemap
+    Matrix fboViews[6] = {
+        MatrixLookAt((Vector3){ 0.0f, 0.0f, 0.0f }, (Vector3){  1.0f,  0.0f,  0.0f }, (Vector3){ 0.0f, -1.0f,  0.0f }),
+        MatrixLookAt((Vector3){ 0.0f, 0.0f, 0.0f }, (Vector3){ -1.0f,  0.0f,  0.0f }, (Vector3){ 0.0f, -1.0f,  0.0f }),
+        MatrixLookAt((Vector3){ 0.0f, 0.0f, 0.0f }, (Vector3){  0.0f,  1.0f,  0.0f }, (Vector3){ 0.0f,  0.0f,  1.0f }),
+        MatrixLookAt((Vector3){ 0.0f, 0.0f, 0.0f }, (Vector3){  0.0f, -1.0f,  0.0f }, (Vector3){ 0.0f,  0.0f, -1.0f }),
+        MatrixLookAt((Vector3){ 0.0f, 0.0f, 0.0f }, (Vector3){  0.0f,  0.0f,  1.0f }, (Vector3){ 0.0f, -1.0f,  0.0f }),
+        MatrixLookAt((Vector3){ 0.0f, 0.0f, 0.0f }, (Vector3){  0.0f,  0.0f, -1.0f }, (Vector3){ 0.0f, -1.0f,  0.0f })
+    };
+
+    rlViewport(0, 0, size, size);   // Set viewport to current fbo dimensions
+
+    for (int i = 0; i < 6; i++)
+    {
+        rlSetUniformMatrix(shader.locs[SHADER_LOC_MATRIX_VIEW], fboViews[i]);
+        rlFramebufferAttach(fbo, cubemap.id, RL_ATTACHMENT_COLOR_CHANNEL0, RL_ATTACHMENT_CUBEMAP_POSITIVE_X + i, 0);
+
+        rlEnableFramebuffer(fbo);
+        rlSetTexture(panorama.id);   // WARNING: It must be called after enabling current framebuffer if using internal batch system!
+
+        rlClearScreenBuffers();
+        DrawCubeV(Vector3Zero(), Vector3One(), WHITE);
+        rlDrawRenderBatchActive();
+    }
+    //------------------------------------------------------------------------------------------
+
+    // STEP 3: Unload framebuffer and reset state
+    //------------------------------------------------------------------------------------------
+    rlDisableShader();          // Unbind shader
+    rlDisableTexture();         // Unbind texture
+    rlDisableFramebuffer();     // Unbind framebuffer
+    rlUnloadFramebuffer(fbo);   // Unload framebuffer (and automatically attached depth texture/renderbuffer)
+
+    // Reset viewport dimensions to default
+    rlViewport(0, 0, rlGetFramebufferWidth(), rlGetFramebufferHeight());
+    rlEnableBackfaceCulling();
+    //------------------------------------------------------------------------------------------
+
+    cubemap.width = size;
+    cubemap.height = size;
+    cubemap.mipmaps = 1;
+    cubemap.format = PIXELFORMAT_UNCOMPRESSED_R32G32B32;
+
+    return cubemap;
+}