add shaders_write_depth example

examples/shaders/resources/shaders/glsl330/write_depth.fs

@@ -0,0 +1,20 @@
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+void main()
+{
+    vec4 texelColor = texture(texture0, fragTexCoord);
+    
+    finalColor = texelColor*colDiffuse*fragColor;
+    gl_FragDepth = 1.0 - finalColor.z;
+}

examples/shaders/shaders_write_depth.py

@@ -0,0 +1,128 @@
+from pyray import *
+import raylib as rl
+
+#------------------------------------------------------------------------------------
+# Define custom functions required for the example
+#------------------------------------------------------------------------------------
+# Load custom render texture, create a writable depth texture buffer
+def LoadRenderTextureDepthTex(width, height):
+
+    target =  RenderTexture()
+
+    target.id = rl_load_framebuffer(width, height)   # Load an empty framebuffer
+
+    if target.id > 0:
+
+        rl_enable_framebuffer(target.id)
+
+        # Create color texture (default to RGBA)
+        target.texture.id = rl_load_texture(None, width, height, PixelFormat.PIXELFORMAT_UNCOMPRESSED_R8G8B8A8, 1)
+        target.texture.width = width
+        target.texture.height = height
+        target.texture.format = PixelFormat.PIXELFORMAT_UNCOMPRESSED_R8G8B8A8
+        target.texture.mipmaps = 1
+
+        # Create depth texture buffer (instead of raylib default renderbuffer)
+        target.depth.id = rl_load_texture_depth(width, height, False)
+        target.depth.width = width
+        target.depth.height = height
+        target.depth.format = 19       #DEPTH_COMPONENT_24BIT?
+        target.depth.mipmaps = 1
+
+        # Attach color texture and depth texture to FBO
+        rl_framebuffer_attach(target.id, target.texture.id, rl.RL_ATTACHMENT_COLOR_CHANNEL0, rl.RL_ATTACHMENT_TEXTURE2D, 0)
+        rl_framebuffer_attach(target.id, target.depth.id, rl.RL_ATTACHMENT_DEPTH, rl.RL_ATTACHMENT_TEXTURE2D, 0)
+
+        # Check if fbo is complete with attachments (valid)
+        if rl_framebuffer_complete(target.id):
+            print(f"FBO: [{target.id}] Framebuffer object created successfully")
+
+        rl_disable_framebuffer()
+
+    else:
+        print("FBO: Framebuffer object can not be created")
+
+    return target
+
+
+# Unload render texture from GPU memory (VRAM)
+def UnloadRenderTextureDepthTex(target):
+
+    if target.id > 0:
+
+        # Color texture attached to FBO is deleted
+        rl_unload_texture(target.texture.id)
+        rl_unload_texture(target.depth.id)
+
+        # NOTE: Depth texture is automatically
+        # queried and deleted before deleting framebuffer
+        rl_unload_framebuffer(target.id)
+
+
+
+screenWidth = 800
+screenHeight = 450
+
+init_window(screenWidth, screenHeight, "raylib [shaders] example - write depth buffer")
+
+# The shader inverts the depth buffer by writing into it by `gl_FragDepth = 1 - gl_FragCoord.z`
+shader = load_shader("","resources/shaders/glsl330/write_depth.fs")
+
+# Use Customized function to create writable depth texture buffer
+target = LoadRenderTextureDepthTex(screenWidth, screenHeight)
+
+# Define the camera to look into our 3d world
+camera = Camera3D()
+camera.position = (2.0, 2.0, 3.0)     # Camera position
+camera.target = (0.0, 0.5, 0.0)     # Camera looking at point
+camera.up = (0.0, 1.0, 0.0)           # Camera up vector (rotation towards target)
+camera.fovy = 45.0                                # Camera field-of-view Y
+camera.projection = CameraProjection.CAMERA_PERSPECTIVE              # Camera projection type
+
+
+set_target_fps(60)                   # Set our game to run at 60 frames-per-second
+#--------------------------------------------------------------------------------------
+
+# Main game loop
+while not window_should_close():        # Detect window close button or ESC key
+
+    # Update
+    #----------------------------------------------------------------------------------
+    update_camera(camera, CameraMode.CAMERA_ORBITAL)
+    #----------------------------------------------------------------------------------
+
+    # Draw
+    #----------------------------------------------------------------------------------
+
+    # Draw into our custom render texture (framebuffer)
+    begin_texture_mode(target)
+    clear_background(WHITE)
+
+    begin_mode_3d(camera)
+    begin_shader_mode(shader)
+    draw_cube_wires_v((0.0, 0.5, 1.0) , (1.0,1.0, 1.0), RED)
+    draw_cube_v((0.0, 0.5, 1.0) , (1.0, 1.0, 1.0) , PURPLE)
+    draw_cube_wires_v((0.0, 0.5, -1.0), (1.0, 1.0, 1.0) , DARKGREEN)
+    draw_cube_v((0.0, 0.5, -1.0) , (1.0, 1.0, 1.0) , YELLOW)
+    draw_grid(10, 1.0)
+    end_shader_mode()
+    end_mode_3d()
+    end_texture_mode()
+
+    # Draw into screen our custom render texture
+    begin_drawing()
+    clear_background(RAYWHITE)
+
+    draw_texture_rec(target.texture, Rectangle(0, 0, screenWidth, -screenHeight) , (0, 0) , WHITE)
+    draw_fps(10, 10)
+    end_drawing()
+
+
+# De-Initialization
+#--------------------------------------------------------------------------------------
+UnloadRenderTextureDepthTex(target)
+unload_shader(shader)
+
+close_window()        # Close window and OpenGL context
+
+