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7 changed files with 154 additions and 266 deletions
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109
CMakeLists.txt
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@ -1,74 +1,9 @@
cmake_minimum_required(VERSION 4.0)
cmake_minimum_required(VERSION 3.22)
project(sdl_project)
set(CMAKE_C_STANDARD 23)
# 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 ${sdl2_gfx_SOURCE_DIR}/sdl2_gfx-src)
target_link_libraries(SDL2_gfx PUBLIC SDL2::SDL2)
# add SDL2_ttf support
#set(SDL2TTF_VENDORED ON)
#find_package(SDL2_ttf QUIET)
#if (NOT SDL2_ttf_FOUND)
# message(STATUS "Getting SDL2_ttf from Github")
# include_dependency(SDL2_ttf https://github.com/libsdl-org/SDL_ttf.git release-2.22.0)
#else()
# message(STATUS "Using local SDL2_ttf")
#endif()
set(CMAKE_C_STANDARD 11)
# Must set the path to the main.cpp, for example: scripts/main.cpp if it is inside a folder
add_executable(${PROJECT_NAME} scripts/main.c
scripts/array.c
scripts/vector.c
@ -79,36 +14,12 @@ add_executable(${PROJECT_NAME} scripts/main.c
scripts/texture.c
scripts/swap.c
scripts/upng.c
scripts/display.c
)
scripts/display.c)
# Target include directories for non-gfx libs
target_include_directories(
${PROJECT_NAME}
PUBLIC
${SDL2_INCLUDE_DIRS}
${SDL2_IMAGE_INCLUDE_DIRS}
# ${SDL2_TTF_INCLUDE_DIRS}
${sdl2_gfx_SOURCE_DIR} # Add SDL2_gfx headers directory
)
# --- SDL2 SETUP ---
set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules)
set(SDL2_PATH "SDL2/x86_64-w64-mingw32")
# link all libraries to the project
target_link_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()
find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIR})
target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARY} ${SDL2_IMAGE_LIBRARIES})

BIN
cmake-build-debug/SDL2.dll
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Binary file not shown.

19
scripts/display.c
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@ -2,10 +2,7 @@
#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;
@ -17,19 +14,19 @@ 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(
"3D Renderer",
NULL,
SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED,
window_width,
window_height,
SDL_WINDOW_SHOWN
SDL_WINDOW_BORDERLESS
);
if (!window) {
fprintf(stderr, "Error creating SDL window.\n");
@ -107,14 +104,6 @@ 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);

2
scripts/display.h
View File

@ -25,7 +25,6 @@ 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;
@ -37,7 +36,6 @@ 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

29
scripts/main.c
View File

@ -33,9 +33,8 @@ void setup(void) {
render_method = RENDER_TEXTURED_WIRE;
cull_method = CULL_BACKFACE;
// Allocate the required memory in bytes to hold the color buffer and z buffer
// Allocate the required memory in bytes to hold the color 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(
@ -208,6 +207,9 @@ void update(void) {
projected_points[j].y += (window_height / 2.0);
}
// Calculate the average depth for each face based on the vertices after transformation
float avg_depth = (transformed_vertices[0].z + transformed_vertices[1].z + transformed_vertices[2].z) / 3.0;
// Calculate the shade intensity based on how aliged is the normal with the flipped light direction ray
float light_intensity_factor = -vec3_dot(normal, light.direction);
@ -226,11 +228,25 @@ void update(void) {
{ mesh_face.c_uv.u, mesh_face.c_uv.v }
},
.color = triangle_color,
.avg_depth = avg_depth
};
// 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;
}
}
}
}
///////////////////////////////////////////////////////////////////////////////
@ -249,9 +265,9 @@ void render(void) {
// Draw filled triangle
if (render_method == RENDER_FILL_TRIANGLE || render_method == RENDER_FILL_TRIANGLE_WIRE) {
draw_filled_triangle(
triangle.points[0].x, triangle.points[0].y, triangle.points[0].z, triangle.points[0].w, // vertex A
triangle.points[1].x, triangle.points[1].y, triangle.points[1].z, triangle.points[1].w, // vertex B
triangle.points[2].x, triangle.points[2].y, triangle.points[2].z, triangle.points[2].w, // vertex C
triangle.points[0].x, triangle.points[0].y, // vertex A
triangle.points[1].x, triangle.points[1].y, // vertex B
triangle.points[2].x, triangle.points[2].y, // vertex C
triangle.color
);
}
@ -289,9 +305,7 @@ void render(void) {
render_color_buffer();
clear_color_buffer(0xFF000000);
clear_z_buffer();
SDL_RenderPresent(renderer);
}
@ -301,7 +315,6 @@ 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);

253
scripts/triangle.c
View File

@ -2,6 +2,122 @@
#include "swap.h"
#include "triangle.h"
///////////////////////////////////////////////////////////////////////////////
// Draw a filled a triangle with a flat bottom
///////////////////////////////////////////////////////////////////////////////
//
// (x0,y0)
// / \
// / \
// / \
// / \
// / \
// (x1,y1)------(x2,y2)
//
///////////////////////////////////////////////////////////////////////////////
void fill_flat_bottom_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color) {
// Find the two slopes (two triangle legs)
float inv_slope_1 = (float)(x1 - x0) / (y1 - y0);
float inv_slope_2 = (float)(x2 - x0) / (y2 - y0);
// Start x_start and x_end from the top vertex (x0,y0)
float x_start = x0;
float x_end = x0;
// Loop all the scanlines from top to bottom
for (int y = y0; y <= y2; y++) {
draw_line(x_start, y, x_end, y, color);
x_start += inv_slope_1;
x_end += inv_slope_2;
}
}
///////////////////////////////////////////////////////////////////////////////
// Draw a filled a triangle with a flat top
///////////////////////////////////////////////////////////////////////////////
//
// (x0,y0)------(x1,y1)
// \ /
// \ /
// \ /
// \ /
// \ /
// (x2,y2)
//
///////////////////////////////////////////////////////////////////////////////
void fill_flat_top_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color) {
// Find the two slopes (two triangle legs)
float inv_slope_1 = (float)(x2 - x0) / (y2 - y0);
float inv_slope_2 = (float)(x2 - x1) / (y2 - y1);
// Start x_start and x_end from the bottom vertex (x2,y2)
float x_start = x2;
float x_end = x2;
// Loop all the scanlines from bottom to top
for (int y = y2; y >= y0; y--) {
draw_line(x_start, y, x_end, y, color);
x_start -= inv_slope_1;
x_end -= inv_slope_2;
}
}
///////////////////////////////////////////////////////////////////////////////
// Draw a filled triangle with the flat-top/flat-bottom method
// We split the original triangle in two, half flat-bottom and half flat-top
///////////////////////////////////////////////////////////////////////////////
//
// (x0,y0)
// / \
// / \
// / \
// / \
// / \
// (x1,y1)------(Mx,My)
// \_ \
// \_ \
// \_ \
// \_ \
// \ \
// \_ \
// \_\
// \
// (x2,y2)
//
///////////////////////////////////////////////////////////////////////////////
void draw_filled_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color) {
// We need to sort the vertices by y-coordinate ascending (y0 < y1 < y2)
if (y0 > y1) {
int_swap(&y0, &y1);
int_swap(&x0, &x1);
}
if (y1 > y2) {
int_swap(&y1, &y2);
int_swap(&x1, &x2);
}
if (y0 > y1) {
int_swap(&y0, &y1);
int_swap(&x0, &x1);
}
if (y1 == y2) {
// Draw flat-bottom triangle
fill_flat_bottom_triangle(x0, y0, x1, y1, x2, y2, color);
} else if (y0 == y1) {
// Draw flat-top triangle
fill_flat_top_triangle(x0, y0, x1, y1, x2, y2, color);
} else {
// Calculate the new vertex (Mx,My) using triangle similarity
int My = y1;
int Mx = (((x2 - x0) * (y1 - y0)) / (y2 - y0)) + x0;
// Draw flat-bottom triangle
fill_flat_bottom_triangle(x0, y0, x1, y1, Mx, My, color);
// Draw flat-top triangle
fill_flat_top_triangle(x1, y1, Mx, My, x2, y2, color);
}
}
///////////////////////////////////////////////////////////////////////////////
// Draw a triangle using three raw line calls
@ -92,59 +208,7 @@ 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;
}
}
void draw_triangle_pixel(
int x, int y, uint32_t color,
vec4_t point_a, vec4_t point_b, vec4_t point_c
) {
vec2_t p = { x, y };
vec2_t a = vec2_from_vec4(point_a);
vec2_t b = vec2_from_vec4(point_b);
vec2_t c = vec2_from_vec4(point_c);
// Calculate the barycentric coordinates of our point 'p' inside the triangle
vec3_t weights = barycentric_weights(a, b, c, p);
float alpha = weights.x;
float beta = weights.y;
float gamma = weights.z;
// Variables to store the interpolated values of U, V, and also 1/w for the current pixel
float interpolated_reciprocal_w;
// Also interpolate the value of 1/w for the current pixel
interpolated_reciprocal_w = (1 / point_a.w) * alpha + (1 / point_b.w) * beta + (1 / point_c.w) * gamma;
// Now we can divide back both interpolated values by 1/w
//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, color);
// update z-buffer value with the 1/w of this current pixel
z_buffer[z_pos] = interpolated_reciprocal_w;
}
draw_pixel(x, y, texture[(texture_width * tex_y) + tex_x]);
}
///////////////////////////////////////////////////////////////////////////////
@ -262,86 +326,3 @@ void draw_textured_triangle(
}
}
}
void draw_filled_triangle(
int x0, int y0, float z0, float w0,
int x1, int y1, float z1, float w1,
int x2, int y2, float z2, float w2,
uint32_t color
) {
// We need to sort the vertices by y-coordinate ascending (y0 < y1 < y2)
if (y0 > y1) {
int_swap(&y0, &y1);
int_swap(&x0, &x1);
float_swap(&z0, &z1);
float_swap(&w0, &w1);
}
if (y1 > y2) {
int_swap(&y1, &y2);
int_swap(&x1, &x2);
float_swap(&z1, &z2);
float_swap(&w1, &w2);
}
if (y0 > y1) {
int_swap(&y0, &y1);
int_swap(&x0, &x1);
float_swap(&z0, &z1);
float_swap(&w0, &w1);
}
// Create vector points and texture coords after we sort the vertices
vec4_t point_a = { x0, y0, z0, w0 };
vec4_t point_b = { x1, y1, z1, w1 };
vec4_t point_c = { x2, y2, z2, w2 };
///////////////////////////////////////////////////////
// Render the upper part of the triangle (flat-bottom)
///////////////////////////////////////////////////////
float inv_slope_1 = 0;
float inv_slope_2 = 0;
if (y1 - y0 != 0) inv_slope_1 = (float)(x1 - x0) / abs(y1 - y0);
if (y2 - y0 != 0) inv_slope_2 = (float)(x2 - x0) / abs(y2 - y0);
if (y1 - y0 != 0) {
for (int y = y0; y <= y1; y++) {
int x_start = x1 + (y - y1) * inv_slope_1;
int x_end = x0 + (y - y0) * inv_slope_2;
if (x_end < x_start) {
int_swap(&x_start, &x_end); // swap if x_start is to the right of x_end
}
for (int x = x_start; x < x_end; x++) {
// Draw our pixel with the color that comes from the texture
draw_triangle_pixel(x, y, color, point_a, point_b, point_c);
}
}
}
///////////////////////////////////////////////////////
// Render the bottom part of the triangle (flat-top)
///////////////////////////////////////////////////////
inv_slope_1 = 0;
inv_slope_2 = 0;
if (y2 - y1 != 0) inv_slope_1 = (float)(x2 - x1) / abs(y2 - y1);
if (y2 - y0 != 0) inv_slope_2 = (float)(x2 - x0) / abs(y2 - y0);
if (y2 - y1 != 0) {
for (int y = y1; y <= y2; y++) {
int x_start = x1 + (y - y1) * inv_slope_1;
int x_end = x0 + (y - y0) * inv_slope_2;
if (x_end < x_start) {
int_swap(&x_start, &x_end); // swap if x_start is to the right of x_end
}
for (int x = x_start; x < x_end; x++) {
// Draw our pixel with the color that comes from the texture
draw_triangle_pixel(x, y, color, point_a, point_b, point_c);
}
}
}
}

8
scripts/triangle.h
View File

@ -23,12 +23,8 @@ typedef struct {
} triangle_t;
void draw_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color);
void draw_filled_triangle(
int x0, int y0, float z0, float w0,
int x1, int y1, float z1, float w1,
int x2, int y2, float z2, float w2,
uint32_t color
);
void draw_filled_triangle(int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color);
void draw_textured_triangle(
int x0, int y0, float z0, float w0, float u0, float v0,
int x1, int y1, float z1, float w1, float u1, float v1,