[C99] Added "Offscreen" example written in C.

This example demonstrates how to render into a texture without ever creating a swap-chain.

.gitignore

@@ -12,6 +12,7 @@ build*/
 # Runtime output files for testing
 Screenshot.*
 Capture.*
+*.Results.png
 
 # Output files from individual tests (Testbed is handled separately)
 tests/Output

examples/C99/CMakeLists.txt

@@ -16,6 +16,7 @@ project(LLGL_ExamplesC99)
 find_source_files(FilesExampleBaseC99 C "${EXAMPLE_C99_PROJECTS_DIR}/ExampleBase")
 
 find_project_source_files( FilesExampleC99_HelloTriangle "${EXAMPLE_C99_PROJECTS_DIR}/HelloTriangle" )
+find_project_source_files( FilesExampleC99_Offscreen "${EXAMPLE_C99_PROJECTS_DIR}/Offscreen" )
 find_project_source_files( FilesExampleC99_Texturing "${EXAMPLE_C99_PROJECTS_DIR}/Texturing" )
 
 
@@ -53,6 +54,7 @@ if(LLGL_BUILD_EXAMPLES AND LLGL_BUILD_WRAPPER_C99)
 
  # C99 wrapper examples
  add_llgl_example_project(Example_C99_HelloTriangle C "${FilesExampleC99_HelloTriangle}" "${EXAMPLE_C99_PROJECT_LIBS}")
+ add_llgl_example_project(Example_C99_Offscreen C "${FilesExampleC99_Offscreen}" "${EXAMPLE_C99_PROJECT_LIBS}")
  add_llgl_example_project(Example_C99_Texturing C "${FilesExampleC99_Texturing}" "${EXAMPLE_C99_PROJECT_LIBS}")
 endif()
 

examples/C99/ExampleBase/ExampleBase.c

@@ -100,22 +100,14 @@ static void mouse_motion_event(LLGLWindow sender, const LLGLOffset2D* motion)
  * Global functions
  */
 
-struct ExampleConfig
-{
- const char* rendererModule;
- uint32_t windowSize[2];
- uint32_t samples;
- bool vsync;
- bool debugger;
-};
-
 static struct ExampleConfig g_Config =
 {
  .rendererModule = "OpenGL",
  .windowSize = { 800, 600 },
  .samples = 8,
  .vsync = true,
  .debugger = false,
+ .noDepthStencil = false
 };
 
 static void update_viewport()
@@ -138,6 +130,33 @@ static float aspect_ratio()
  return (float)swapChainResolution.width / (float)swapChainResolution.height;
 }
 
+void example_config(const ExampleConfig* config)
+{
+ if (config != NULL)
+ {
+ if (config->rendererModule != NULL)
+ g_Config.rendererModule = config->rendererModule;
+ if (config->windowSize[0] != 0)
+ g_Config.windowSize[0] = config->windowSize[0];
+ if (config->windowSize[1] != 0)
+ g_Config.windowSize[1] = config->windowSize[1];
+ g_Config.samples = config->samples;
+ g_Config.vsync = config->vsync;
+ g_Config.debugger = config->debugger;
+ g_Config.noDepthStencil = config->noDepthStencil;
+ }
+ else
+ {
+ g_Config.rendererModule = "OpenGL";
+ g_Config.windowSize[0] = 800;
+ g_Config.windowSize[1] = 600;
+ g_Config.samples = 8;
+ g_Config.vsync = true;
+ g_Config.debugger = false;
+ g_Config.noDepthStencil = false;
+ }
+}
+
 int example_init(const wchar_t* title)
 {
  // Register standard output as log callback
@@ -155,10 +174,10 @@ int example_init(const wchar_t* title)
  LLGLSwapChainDescriptor swapChainDesc =
  {
  .resolution = { g_Config.windowSize[0], g_Config.windowSize[1] },
- .colorBits = 32, // 32 bits for color information
- .depthBits = 24, // 24 bits for depth comparison
- .stencilBits = 8, // 8 bits for stencil patterns
- .samples = g_Config.samples, // check if LLGL adapts sample count that is too high
+ .colorBits = 32,  // 32 bits for color information
+ .depthBits = (g_Config.noDepthStencil ? 0 : 24), // 24 bits for depth comparison
+ .stencilBits = (g_Config.noDepthStencil ? 0 : 8), // 8 bits for stencil patterns
+ .samples = g_Config.samples,  // check if LLGL adapts sample count that is too high
  };
  g_swapChain = llglCreateSwapChain(&swapChainDesc);
 
@@ -249,10 +268,38 @@ bool example_poll_events()
 void perspective_projection(float outProjection[4][4], float aspectRatio, float nearPlane, float farPlane, float fieldOfView)
 {
  const int rendererID = llglGetRendererID();
- if (rendererID == LLGL_RENDERERID_OPENGL || rendererID == LLGL_RENDERERID_VULKAN)
- build_perspective_projection(outProjection, aspectRatio, nearPlane, farPlane, fieldOfView, /*isUnitCube:*/ true);
- else
- build_perspective_projection(outProjection, aspectRatio, nearPlane, farPlane, fieldOfView, /*isUnitCube:*/ false);
+ const bool isUnitCube = (rendererID == LLGL_RENDERERID_OPENGL || rendererID == LLGL_RENDERERID_VULKAN);
+ build_perspective_projection(outProjection, aspectRatio, nearPlane, farPlane, fieldOfView, isUnitCube);
+}
+
+static void build_orthogonal_projection(float m[4][4], float width, float height, float nearPlane, float farPlane, bool isUnitCube)
+{
+ m[0][0] = 2.0f / width;
+ m[0][1] = 0.0f;
+ m[0][2] = 0.0f;
+ m[0][3] = 0.0f;
+
+ m[1][0] = 0.0f;
+ m[1][1] = 2.0f / height;
+ m[1][2] = 0.0f;
+ m[1][3] = 0.0f;
+
+ m[2][0] = 0.0f;
+ m[2][1] = 0.0f;
+ m[2][2] = (isUnitCube ? 2.0f/(farPlane - nearPlane) : 1.0f/(farPlane - nearPlane));
+ m[3][2] = 0.0f;
+
+ m[3][0] = 0.0f;
+ m[3][1] = 0.0f;
+ m[2][3] = (isUnitCube ? -(farPlane + nearPlane)/(farPlane - nearPlane) : -nearPlane/(farPlane - nearPlane));
+ m[3][3] = 1.0f;
+}
+
+void orthogonal_projection(float outProjection[4][4], float width, float height, float nearPlane, float farPlane)
+{
+ const int rendererID = llglGetRendererID();
+ const bool isUnitCube = (rendererID == LLGL_RENDERERID_OPENGL || rendererID == LLGL_RENDERERID_VULKAN);
+ build_orthogonal_projection(outProjection, width, height, nearPlane, farPlane, isUnitCube);
 }
 
 void get_textured_cube(const TexturedVertex** outVertices, size_t* outVertexCount, const uint32_t** outIndices, size_t* outIndexCount)

examples/C99/ExampleBase/ExampleBase.h

@@ -26,6 +26,17 @@
  * Structures
  */
 
+typedef struct ExampleConfig
+{
+ const char* rendererModule;
+ uint32_t windowSize[2];
+ uint32_t samples;
+ bool vsync;
+ bool debugger;
+ bool noDepthStencil;
+}
+ExampleConfig;
+
 typedef struct TexturedVertex
 {
  float position[3];
@@ -91,6 +102,9 @@ extern float g_projection[4][4];
  * Global functions
  */
 
+// Configures the example setup. If used, it must be called before example_init(). If this is NULL, the defualt configuration will be used.
+void example_config(const ExampleConfig* config);
+
 // Initializes the example with the specified title and returns a non-zero error code if initialization failed.
 int example_init(const wchar_t* title);
 
@@ -103,6 +117,9 @@ bool example_poll_events();
 // Builds a perspective projection matrix.
 void perspective_projection(float outProjection[4][4], float aspectRatio, float nearPlane, float farPlane, float fieldOfView);
 
+// Builds an orthogonal projection matrix.
+void orthogonal_projection(float outProjection[4][4], float width, float height, float nearPlane, float farPlane);
+
 // Returns the pointers the vertex and index data of a textured cube.
 void get_textured_cube(const TexturedVertex** outVertices, size_t* outVertexCount, const uint32_t** outIndices, size_t* outIndexCount);