refactor for desktop, z-buffer for textured triangles

CMakeLists.txt

@@ -1,9 +1,74 @@
-cmake_minimum_required(VERSION 3.22)
+cmake_minimum_required(VERSION 4.0)
 project(sdl_project)
+set(CMAKE_C_STANDARD 23)
 
-set(CMAKE_C_STANDARD 11)
+# Include the command that downloads libraries
+include(FetchContent)
+
+# define a function for adding git dependencies
+function(include_dependency libName gitURL gitTag)
+    FetchContent_Declare(${libName}
+            GIT_REPOSITORY ${gitURL}
+            GIT_TAG        ${gitTag}
+            GIT_SHALLOW    TRUE
+            GIT_PROGRESS   TRUE
+    )
+    FetchContent_MakeAvailable(${libName})
+endfunction()
+
+# add SDL2 support
+find_package(SDL2 QUIET)
+if (NOT SDL2_FOUND)
+    message(STATUS "Getting SDL2 from Github")
+    include_dependency(SDL2 https://github.com/libsdl-org/SDL.git release-2.30.8)
+else()
+    message(STATUS "Using local SDL2")
+endif()
+
+# add SDL2_image support
+find_package(SDL2_image QUIET)
+if (NOT SDL2_image_FOUND)
+    message(STATUS "Getting SDL2_image from Github")
+    include_dependency(SDL2_image https://github.com/libsdl-org/SDL_image.git release-2.8.2)
+else()
+    message(STATUS "Using local SDL2_image")
+endif()
+
+## add SDL2_gfx support (NO find_package, fetch and add it manually)
+#find_package(SDL2_gfx QUIET)
+#if (NOT SDL2_gfx)
+#    message(STATUS "Getting SDL2_gfx from Github")
+#    include_dependency(SDL2_gfx https://github.com/giroletm/SDL2_gfx.git release-1.0.4)
+#else()
+#    message(STATUS "Using local SDL2_gfx")
+#endif()
+
+# SDL2_gfx (DO NOT use the function for this one)
+FetchContent_Declare(
+        SDL2_gfx
+        GIT_REPOSITORY https://github.com/giroletm/SDL2_gfx.git
+        GIT_TAG master
+)
+FetchContent_MakeAvailable(SDL2_gfx)
+message(STATUS "sdl2_gfx_SOURCE_DIR is: ${sdl2_gfx_SOURCE_DIR}")
+add_library(SDL2_gfx STATIC
+        ${sdl2_gfx_SOURCE_DIR}/SDL2_gfxPrimitives.c
+        ${sdl2_gfx_SOURCE_DIR}/SDL2_rotozoom.c
+)
+
+target_include_directories(SDL2_gfx PUBLIC ${sdl2_gfx_SOURCE_DIR}/sdl2_gfx-src)
+target_link_libraries(SDL2_gfx PUBLIC SDL2::SDL2)
+
+# add SDL2_ttf support
+#set(SDL2TTF_VENDORED ON)
+#find_package(SDL2_ttf QUIET)
+#if (NOT SDL2_ttf_FOUND)
+#    message(STATUS "Getting SDL2_ttf from Github")
+#    include_dependency(SDL2_ttf https://github.com/libsdl-org/SDL_ttf.git release-2.22.0)
+#else()
+#    message(STATUS "Using local SDL2_ttf")
+#endif()
 
-# Must set the path to the main.cpp, for example: scripts/main.cpp if it is inside a folder
 add_executable(${PROJECT_NAME} scripts/main.c
         scripts/array.c
         scripts/vector.c
@@ -14,12 +79,36 @@ add_executable(${PROJECT_NAME} scripts/main.c
         scripts/texture.c
         scripts/swap.c
         scripts/upng.c
-        scripts/display.c)
+        scripts/display.c
+)
 
-# --- SDL2 SETUP ---
+# Target include directories for non-gfx libs
-set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules)
+target_include_directories(
-set(SDL2_PATH "SDL2/x86_64-w64-mingw32")
+        ${PROJECT_NAME}
+        PUBLIC
+        ${SDL2_INCLUDE_DIRS}
+        ${SDL2_IMAGE_INCLUDE_DIRS}
+#        ${SDL2_TTF_INCLUDE_DIRS}
+        ${sdl2_gfx_SOURCE_DIR}    # Add SDL2_gfx headers directory
+)
 
-find_package(SDL2 REQUIRED)
+# link all libraries to the project
-include_directories(${SDL2_INCLUDE_DIR})
+target_link_libraries(
-target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARY} ${SDL2_IMAGE_LIBRARIES})
+        ${PROJECT_NAME}
+        PRIVATE
+        SDL2::SDL2
+        SDL2::SDL2main
+        SDL2_image::SDL2_image
+#        SDL2_ttf::SDL2_ttf
+        SDL2_gfx                 # Link in the SDL2_gfx library we added
+)
+
+if (WIN32)
+    add_custom_command(
+            TARGET ${PROJECT_NAME} POST_BUILD
+            COMMAND "${CMAKE_COMMAND}" -E copy_if_different "$<TARGET_FILE:SDL2::SDL2>" "$<TARGET_FILE_DIR:sdl_project>"
+            COMMAND "${CMAKE_COMMAND}" -E copy_if_different "$<TARGET_FILE:SDL2_image::SDL2_image>" "$<TARGET_FILE_DIR:sdl_project>"
+            #COMMAND "${CMAKE_COMMAND}" -E copy_if_different "$<TARGET_FILE:SDL2_ttf::SDL2_ttf>" "$<TARGET_FILE_DIR:sdl_project>"
+            VERBATIM
+    )
+endif()

scripts/display.c

@@ -2,7 +2,10 @@
 #include "display.h"
 SDL_Window* window = NULL;
 SDL_Renderer* renderer = NULL;
+
 uint32_t* color_buffer = NULL;
+float* z_buffer = NULL;
+
 SDL_Texture* color_buffer_texture = NULL;
 int window_width = 800;
 int window_height = 600;
@@ -14,19 +17,19 @@ bool initialize_window(void) {
     }
 
     // Set width and height of the SDL window with the max screen resolution
-    SDL_DisplayMode display_mode;
+    /*SDL_DisplayMode display_mode;
     SDL_GetCurrentDisplayMode(0, &display_mode);
     window_width = display_mode.w;
     window_height = display_mode.h;
-
+*/
     // Create a SDL Window
     window = SDL_CreateWindow(
-        NULL,
+        "3D Renderer",
         SDL_WINDOWPOS_CENTERED,
         SDL_WINDOWPOS_CENTERED,
         window_width,
         window_height,
-        SDL_WINDOW_BORDERLESS
+        SDL_WINDOW_SHOWN
     );
     if (!window) {
         fprintf(stderr, "Error creating SDL window.\n");
@@ -104,6 +107,14 @@ void clear_color_buffer(uint32_t color) {
     }
 }
 
+void clear_z_buffer() {
+    for (int y = 0; y < window_height; y++) {
+        for (int x = 0; x < window_width; x++) {
+            z_buffer[(window_width * y) + x] = 1.0F;
+        }
+    }
+}
+
 void destroy_window(void) {
     SDL_DestroyRenderer(renderer);
     SDL_DestroyWindow(window);

scripts/display.h

@@ -25,6 +25,7 @@ enum render_method {
 extern SDL_Window* window;
 extern SDL_Renderer* renderer;
 extern uint32_t* color_buffer;
+extern float* z_buffer;
 extern SDL_Texture* color_buffer_texture;
 extern int window_width;
 extern int window_height;
@@ -36,6 +37,7 @@ void draw_line(int x0, int y0, int x1, int y1, uint32_t color);
 void draw_rect(int x, int y, int width, int height, uint32_t color);
 void render_color_buffer(void);
 void clear_color_buffer(uint32_t color);
+void clear_z_buffer();
 void destroy_window(void);
 
 #endif

scripts/main.c

@@ -33,8 +33,9 @@ void setup(void) {
     render_method = RENDER_TEXTURED_WIRE;
     cull_method = CULL_BACKFACE;
 
-    // Allocate the required memory in bytes to hold the color buffer
+    // Allocate the required memory in bytes to hold the color buffer and z buffer
     color_buffer = (uint32_t*)malloc(sizeof(uint32_t) * window_width * window_height);
+    z_buffer = (float*)malloc(sizeof(float) * window_width * window_height);
 
     // Creating a SDL texture that is used to display the color buffer
     color_buffer_texture = SDL_CreateTexture(
@@ -234,19 +235,6 @@ void update(void) {
         // Save the projected triangle in the array of triangles to render
         array_push(triangles_to_render, projected_triangle);
     }
-
-    // Sort the triangles to render by their avg_depth
-    int num_triangles = array_length(triangles_to_render);
-    for (int i = 0; i < num_triangles; i++) {
-        for (int j = i; j < num_triangles; j++) {
-            if (triangles_to_render[i].avg_depth < triangles_to_render[j].avg_depth) {
-                // Swap the triangles positions in the array
-                triangle_t temp = triangles_to_render[i];
-                triangles_to_render[i] = triangles_to_render[j];
-                triangles_to_render[j] = temp;
-            }
-        }
-    }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -305,7 +293,9 @@ void render(void) {
 
     render_color_buffer();
 
+
     clear_color_buffer(0xFF000000);
+    clear_z_buffer();
 
     SDL_RenderPresent(renderer);
 }
@@ -315,6 +305,7 @@ void render(void) {
 ///////////////////////////////////////////////////////////////////////////////
 void free_resources(void) {
     free(color_buffer);
+    free(z_buffer);
     array_free(mesh.faces);
     array_free(mesh.vertices);
     upng_free(png_texture);

scripts/triangle.c

@@ -208,7 +208,19 @@ void draw_texel(
     int tex_y = abs((int)(interpolated_v * texture_height)) % texture_height;
     //tex_x = SDL_clamp(tex_x, 0, texture_width);
     //tex_y = SDL_clamp(tex_y, 0, texture_height);
+
+    int z_pos = (window_width * y) + x;
+
+    // Adjust 1/w so the pixels that are closer to the camera have smaller values
+    interpolated_reciprocal_w = 1.0 - interpolated_reciprocal_w;
+
+    // only draw pixel if depth value is less than one previously stored in z-buffer
+    if (interpolated_reciprocal_w < z_buffer[z_pos]) {
         draw_pixel(x, y, texture[(texture_width * tex_y) + tex_x]);
+
+        // update z-buffer value with the 1/w of this current pixel
+        z_buffer[z_pos] = interpolated_reciprocal_w;
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -326,3 +338,4 @@ void draw_textured_triangle(
         }
     }
 }
+