Review BeginTextureMode() usage

Moved outside BeginDrawing()/EndDrawing() to illustrate drawing is happening to an external texture (not screen)

examples/core/core_split_screen.c

@@ -89,7 +89,7 @@ int main(void)
         // this moves thigns at 10 world units per second, regardless of the actual FPS
         float offsetThisFrame = 10.0f*GetFrameTime();
 
-        // Move player 1 forward and backwards (no turning)
+        // Move Player1 forward and backwards (no turning)
         if (IsKeyDown(KEY_W))
         {
             cameraPlayer1.position.z += offsetThisFrame;
@@ -101,7 +101,7 @@ int main(void)
             cameraPlayer1.target.z -= offsetThisFrame;
         }
 
-        // Move player 2 forward and backwards (no turning)
+        // Move Player2 forward and backwards (no turning)
         if (IsKeyDown(KEY_UP))
         {
             cameraPlayer2.position.x += offsetThisFrame;
@@ -116,7 +116,7 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        // Draw player 1's view to the render texture
+        // Draw Player1 view to the render texture
         BeginTextureMode(screenPlayer1);
             ClearBackground(SKYBLUE);
             BeginMode3D(cameraPlayer1);
@@ -125,7 +125,7 @@ int main(void)
             DrawText("PLAYER1 W/S to move", 0, 0, 20, RED);
         EndTextureMode();
 
-        // Draw player 2's view to the render texture
+        // Draw Player2 view to the render texture
         BeginTextureMode(screenPlayer2);
             ClearBackground(SKYBLUE);
             BeginMode3D(cameraPlayer2);
@@ -134,19 +134,19 @@ int main(void)
             DrawText("PLAYER2 UP/DOWN to move", 0, 0, 20, BLUE);
         EndTextureMode();
 
-        // Draw both view render textures to the screen side by side
+        // Draw both views render textures to the screen side by side
         BeginDrawing();
             ClearBackground(BLACK);
-            DrawTextureRec(screenPlayer1.texture, splitScreenRect, (Vector2) { 0, 0 }, WHITE);
+            DrawTextureRec(screenPlayer1.texture, splitScreenRect, (Vector2){ 0, 0 }, WHITE);
-            DrawTextureRec(screenPlayer2.texture, splitScreenRect, (Vector2) { screenWidth/2.0f, 0 }, WHITE);
+            DrawTextureRec(screenPlayer2.texture, splitScreenRect, (Vector2){ screenWidth/2.0f, 0 }, WHITE);
         EndDrawing();
     }
 
     // De-Initialization
     //--------------------------------------------------------------------------------------
-    UnloadRenderTexture(screenPlayer1);
+    UnloadRenderTexture(screenPlayer1); // Unload render texture
-    UnloadRenderTexture(screenPlayer2);
+    UnloadRenderTexture(screenPlayer2); // Unload render texture
-    UnloadTexture(textureGrid);
+    UnloadTexture(textureGrid);         // Unload texture
     
     CloseWindow();                      // Close window and OpenGL context
     //--------------------------------------------------------------------------------------

examples/core/core_vr_simulator.c

@@ -105,10 +105,6 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        BeginDrawing();
-
-            ClearBackground(RAYWHITE);
-
         BeginTextureMode(target);
             ClearBackground(RAYWHITE);
             BeginVrStereoMode(config);
@@ -122,13 +118,13 @@ int main(void)
             EndVrStereoMode();
         EndTextureMode();
         
+        BeginDrawing();
+            ClearBackground(RAYWHITE);
             BeginShaderMode(distortion);
                 DrawTextureRec(target.texture, (Rectangle){ 0, 0, (float)target.texture.width,
                               (float)-target.texture.height }, (Vector2){ 0.0f, 0.0f }, WHITE);
             EndShaderMode();
-
             DrawFPS(10, 10);
-
         EndDrawing();
         //----------------------------------------------------------------------------------
     }

examples/core/core_window_letterbox.c

@@ -79,28 +79,24 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        BeginDrawing();
-            ClearBackground(BLACK);
-
         // Draw everything in the render texture, note this will not be rendered on screen, yet
         BeginTextureMode(target);
-
             ClearBackground(RAYWHITE);  // Clear render texture background color
 
             for (int i = 0; i < 10; i++) DrawRectangle(0, (gameScreenHeight/10)*i, gameScreenWidth, gameScreenHeight/10, colors[i]);
 
             DrawText("If executed inside a window,\nyou can resize the window,\nand see the screen scaling!", 10, 25, 20, WHITE);
-
             DrawText(TextFormat("Default Mouse: [%i , %i]", (int)mouse.x, (int)mouse.y), 350, 25, 20, GREEN);
             DrawText(TextFormat("Virtual Mouse: [%i , %i]", (int)virtualMouse.x, (int)virtualMouse.y), 350, 55, 20, YELLOW);
-
         EndTextureMode();
         
-            // Draw RenderTexture2D to window, properly scaled
+        BeginDrawing();
+            ClearBackground(BLACK);     // Clear screen background
+
+            // Draw render texture to screen, properly scaled
             DrawTexturePro(target.texture, (Rectangle){ 0.0f, 0.0f, (float)target.texture.width, (float)-target.texture.height },
                            (Rectangle){ (GetScreenWidth() - ((float)gameScreenWidth*scale))*0.5f, (GetScreenHeight() - ((float)gameScreenHeight*scale))*0.5f,
                            (float)gameScreenWidth*scale, (float)gameScreenHeight*scale }, (Vector2){ 0, 0 }, 0.0f, WHITE);
-
         EndDrawing();
         //--------------------------------------------------------------------------------------
     }

examples/shaders/shaders_custom_uniform.c

@@ -86,38 +86,29 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        BeginDrawing();
-
-            ClearBackground(RAYWHITE);
-
         BeginTextureMode(target);       // Enable drawing to texture
-
             ClearBackground(RAYWHITE);  // Clear texture background
 
             BeginMode3D(camera);        // Begin 3d mode drawing
-
                 DrawModel(model, position, 0.5f, WHITE);   // Draw 3d model with texture
-
                 DrawGrid(10, 1.0f);     // Draw a grid
-
             EndMode3D();                // End 3d mode drawing, returns to orthographic 2d mode
 
             DrawText("TEXT DRAWN IN RENDER TEXTURE", 200, 10, 30, RED);
-
         EndTextureMode();               // End drawing to texture (now we have a texture available for next passes)
 
-            BeginShaderMode(shader);
+        BeginDrawing();
+            ClearBackground(RAYWHITE);  // Clear screen background
 
+            // Enable shader using the custom uniform
+            BeginShaderMode(shader);
                 // NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
                 DrawTextureRec(target.texture, (Rectangle){ 0, 0, (float)target.texture.width, (float)-target.texture.height }, (Vector2){ 0, 0 }, WHITE);
-
             EndShaderMode();
 
             // Draw some 2d text over drawn texture
             DrawText("(c) Barracks 3D model by Alberto Cano", screenWidth - 220, screenHeight - 20, 10, GRAY);
-
             DrawFPS(10, 10);
-
         EndDrawing();
         //----------------------------------------------------------------------------------
     }

examples/shaders/shaders_eratosthenes.c

@@ -59,10 +59,6 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        BeginDrawing();
-
-            ClearBackground(RAYWHITE);
-
         BeginTextureMode(target);       // Enable drawing to texture
             ClearBackground(BLACK);     // Clear the render texture
 
@@ -73,11 +69,13 @@ int main(void)
             DrawRectangle(0, 0, GetScreenWidth(), GetScreenHeight(), BLACK);
         EndTextureMode();               // End drawing to texture (now we have a blank texture available for the shader)
 
+        BeginDrawing();
+            ClearBackground(RAYWHITE);  // Clear screen background
+
             BeginShaderMode(shader);
                 // NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
                 DrawTextureRec(target.texture, (Rectangle){ 0, 0, (float)target.texture.width, (float)-target.texture.height }, (Vector2){ 0.0f, 0.0f }, WHITE);
             EndShaderMode();
-
         EndDrawing();
         //----------------------------------------------------------------------------------
     }
@@ -85,7 +83,7 @@ int main(void)
     // De-Initialization
     //--------------------------------------------------------------------------------------
     UnloadShader(shader);               // Unload shader
-    UnloadRenderTexture(target);    // Unload texture
+    UnloadRenderTexture(target);        // Unload render texture
 
     CloseWindow();                      // Close window and OpenGL context
     //--------------------------------------------------------------------------------------

examples/shaders/shaders_julia_set.c

@@ -145,10 +145,6 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        BeginDrawing();
-
-            ClearBackground(BLACK);         // Clear the screen of the previous frame.
-
         // Using a render texture to draw Julia set
         BeginTextureMode(target);       // Enable drawing to texture
             ClearBackground(BLACK);     // Clear the render texture
@@ -160,6 +156,9 @@ int main(void)
             DrawRectangle(0, 0, GetScreenWidth(), GetScreenHeight(), BLACK);
         EndTextureMode();
             
+        BeginDrawing();
+            ClearBackground(BLACK);     // Clear screen background
+
             // Draw the saved texture and rendered julia set with shader
             // NOTE: We do not invert texture on Y, already considered inside shader
             BeginShaderMode(shader);
@@ -176,7 +175,6 @@ int main(void)
                 DrawText("Press KEY_LEFT | KEY_RIGHT to change speed", 10, 60, 10, RAYWHITE);
                 DrawText("Press KEY_SPACE to pause movement animation", 10, 75, 10, RAYWHITE);
             }
-
         EndDrawing();
         //----------------------------------------------------------------------------------
     }

examples/shaders/shaders_postprocessing.c

@@ -124,50 +124,38 @@ int main(void)
 
         // Draw
         //----------------------------------------------------------------------------------
-        BeginDrawing();
-
-            ClearBackground(RAYWHITE);
-
         BeginTextureMode(target);       // Enable drawing to texture
-
             ClearBackground(RAYWHITE);  // Clear texture background
 
             BeginMode3D(camera);        // Begin 3d mode drawing
-
                 DrawModel(model, position, 0.1f, WHITE);   // Draw 3d model with texture
-
                 DrawGrid(10, 1.0f);     // Draw a grid
-
             EndMode3D();                // End 3d mode drawing, returns to orthographic 2d mode
-
         EndTextureMode();               // End drawing to texture (now we have a texture available for next passes)
         
-            // Render previously generated texture using selected postpro shader
+        BeginDrawing();
-            BeginShaderMode(shaders[currentShader]);
+            ClearBackground(RAYWHITE);  // Clear screen background
 
+            // Render generated texture using selected postprocessing shader
+            BeginShaderMode(shaders[currentShader]);
                 // NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
                 DrawTextureRec(target.texture, (Rectangle){ 0, 0, (float)target.texture.width, (float)-target.texture.height }, (Vector2){ 0, 0 }, WHITE);
-
             EndShaderMode();
 
             // Draw 2d shapes and text over drawn texture
             DrawRectangle(0, 9, 580, 30, Fade(LIGHTGRAY, 0.7f));
 
             DrawText("(c) Church 3D model by Alberto Cano", screenWidth - 200, screenHeight - 20, 10, GRAY);
-
             DrawText("CURRENT POSTPRO SHADER:", 10, 15, 20, BLACK);
             DrawText(postproShaderText[currentShader], 330, 15, 20, RED);
             DrawText("< >", 540, 10, 30, DARKBLUE);
-
             DrawFPS(700, 15);
-
         EndDrawing();
         //----------------------------------------------------------------------------------
     }
 
     // De-Initialization
     //--------------------------------------------------------------------------------------
-
     // Unload all postpro shaders
     for (int i = 0; i < MAX_POSTPRO_SHADERS; i++) UnloadShader(shaders[i]);
 

src/core.c

@@ -1942,6 +1942,9 @@ void ClearBackground(Color color)
 // Setup canvas (framebuffer) to start drawing
 void BeginDrawing(void)
 {
+    // WARNING: Previously to BeginDrawing() other render textures drawing could happen,
+    // consequently the measure for update vs draw is not accurate (only the total frame time is accurate)
+    
     CORE.Time.current = GetTime();      // Number of elapsed seconds since InitTimer()
     CORE.Time.update = CORE.Time.current - CORE.Time.previous;
     CORE.Time.previous = CORE.Time.current;
@@ -2045,7 +2048,7 @@ void EndDrawing(void)
         CORE.Time.frame += waitTime;    // Total frame time: update + draw + wait
     }
 
-    PollInputEvents();              // Poll user events
+    PollInputEvents();      // Poll user events (before next frame update)
 #endif
 
 #if defined(SUPPORT_EVENTS_AUTOMATION)