ref: 3a5a5044b179198dba416eaf3a9bb17f7854d191
dir: /src/Backends/Rendering/Software.cpp/
#include "../Rendering.h"
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include "SDL.h"
#include "../../WindowsWrapper.h"
#include "../../Resource.h"
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
typedef struct Backend_Surface
{
unsigned char *pixels;
unsigned int width;
unsigned int height;
unsigned int pitch;
} Backend_Surface;
typedef struct Backend_Glyph
{
unsigned char *pixels;
unsigned int width;
unsigned int height;
} Backend_Glyph;
static SDL_Window *window;
static SDL_Surface *window_sdlsurface;
static SDL_Surface *framebuffer_sdlsurface;
static Backend_Surface framebuffer;
static unsigned char glyph_colour_channels[3];
static Backend_Surface *glyph_destination_surface;
Backend_Surface* Backend_Init(const char *window_title, int screen_width, int screen_height, BOOL fullscreen)
{
window = SDL_CreateWindow(window_title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, screen_width, screen_height, 0);
if (window != NULL)
{
#ifndef _WIN32 // On Windows, we use native icons instead (so we can give the taskbar and window separate icons, like the original EXE does)
size_t resource_size;
const unsigned char *resource_data = FindResource("ICON_MINI", "ICON", &resource_size);
SDL_RWops *rwops = SDL_RWFromConstMem(resource_data, resource_size);
SDL_Surface *icon_surface = SDL_LoadBMP_RW(rwops, 1);
SDL_SetWindowIcon(window, icon_surface);
SDL_FreeSurface(icon_surface);
#endif
if (fullscreen)
SDL_SetWindowFullscreen(window, SDL_WINDOW_FULLSCREEN);
window_sdlsurface = SDL_GetWindowSurface(window);
framebuffer_sdlsurface = SDL_CreateRGBSurfaceWithFormat(0, window_sdlsurface->w, window_sdlsurface->h, 0, SDL_PIXELFORMAT_RGB24);
if (framebuffer_sdlsurface != NULL)
{
framebuffer.pixels = (unsigned char*)framebuffer_sdlsurface->pixels;
framebuffer.width = framebuffer_sdlsurface->w;
framebuffer.height = framebuffer_sdlsurface->h;
framebuffer.pitch = framebuffer_sdlsurface->pitch;
return &framebuffer;
}
else
{
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal error (software rendering backend)", "Could not create framebuffer surface", window);
}
SDL_DestroyWindow(window);
}
else
{
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal error (software rendering backend)", "Could not create window", NULL);
}
return NULL;
}
void Backend_Deinit(void)
{
SDL_FreeSurface(framebuffer_sdlsurface);
SDL_DestroyWindow(window);
}
void Backend_DrawScreen(void)
{
SDL_BlitSurface(framebuffer_sdlsurface, NULL, window_sdlsurface, NULL);
SDL_UpdateWindowSurface(window);
}
Backend_Surface* Backend_CreateSurface(unsigned int width, unsigned int height)
{
Backend_Surface *surface = (Backend_Surface*)malloc(sizeof(Backend_Surface));
if (surface == NULL)
return NULL;
surface->pixels = (unsigned char*)malloc(width * height * 3);
if (surface->pixels == NULL)
{
free(surface);
return NULL;
}
surface->width = width;
surface->height = height;
surface->pitch = width * 3;
return surface;
}
void Backend_FreeSurface(Backend_Surface *surface)
{
if (surface == NULL)
return;
free(surface->pixels);
free(surface);
}
BOOL Backend_IsSurfaceLost(Backend_Surface *surface)
{
(void)surface;
return FALSE;
}
void Backend_RestoreSurface(Backend_Surface *surface)
{
(void)surface;
}
unsigned char* Backend_LockSurface(Backend_Surface *surface, unsigned int *pitch, unsigned int width, unsigned int height)
{
(void)width;
(void)height;
if (surface == NULL)
return NULL;
*pitch = surface->pitch;
return surface->pixels;
}
void Backend_UnlockSurface(Backend_Surface *surface, unsigned int width, unsigned int height)
{
(void)surface;
(void)width;
(void)height;
}
void Backend_Blit(Backend_Surface *source_surface, const RECT *rect, Backend_Surface *destination_surface, long x, long y, BOOL colour_key)
{
if (source_surface == NULL || destination_surface == NULL)
return;
RECT rect_clamped;
rect_clamped.left = rect->left;
rect_clamped.top = rect->top;
rect_clamped.right = rect->right;
rect_clamped.bottom = rect->bottom;
// Clamp the rect and coordinates so we don't write outside the pixel buffer
long overflow;
overflow = 0 - x;
if (overflow > 0)
{
rect_clamped.left += overflow;
x += overflow;
}
overflow = 0 - y;
if (overflow > 0)
{
rect_clamped.top += overflow;
y += overflow;
}
overflow = (x + (rect_clamped.right - rect_clamped.left)) - destination_surface->width;
if (overflow > 0)
{
rect_clamped.right -= overflow;
}
overflow = (y + (rect_clamped.bottom - rect_clamped.top)) - destination_surface->height;
if (overflow > 0)
{
rect_clamped.bottom -= overflow;
}
if (rect_clamped.bottom - rect_clamped.top <= 0)
return;
if (rect_clamped.right - rect_clamped.left <= 0)
return;
// Do the actual blitting
if (colour_key)
{
for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
{
unsigned char *source_pointer = &source_surface->pixels[((rect_clamped.top + j) * source_surface->pitch) + (rect_clamped.left * 3)];
unsigned char *destination_pointer = &destination_surface->pixels[((y + j) * destination_surface->pitch) + (x * 3)];
for (long i = 0; i < rect_clamped.right - rect_clamped.left; ++i)
{
if (source_pointer[0] == 0 && source_pointer[1] == 0 && source_pointer[2] == 0) // Assumes the colour key will always be #000000 (black)
{
source_pointer += 3;
destination_pointer += 3;
}
else
{
*destination_pointer++ = *source_pointer++;
*destination_pointer++ = *source_pointer++;
*destination_pointer++ = *source_pointer++;
}
}
}
}
else
{
for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
{
unsigned char *source_pointer = &source_surface->pixels[((rect_clamped.top + j) * source_surface->pitch) + (rect_clamped.left * 3)];
unsigned char *destination_pointer = &destination_surface->pixels[((y + j) * destination_surface->pitch) + (x * 3)];
memcpy(destination_pointer, source_pointer, (rect_clamped.right - rect_clamped.left) * 3);
}
}
}
void Backend_ColourFill(Backend_Surface *surface, const RECT *rect, unsigned char red, unsigned char green, unsigned char blue)
{
if (surface == NULL)
return;
RECT rect_clamped;
rect_clamped.left = rect->left;
rect_clamped.top = rect->top;
rect_clamped.right = rect->right;
rect_clamped.bottom = rect->bottom;
// Clamp the rect so it doesn't write outside the pixel buffer
long overflow;
overflow = 0 - rect_clamped.left;
if (overflow > 0)
{
rect_clamped.left += overflow;
}
overflow = 0 - rect_clamped.top;
if (overflow > 0)
{
rect_clamped.top += overflow;
}
overflow = rect_clamped.right - surface->width;
if (overflow > 0)
{
rect_clamped.right -= overflow;
}
overflow = rect_clamped.bottom - surface->height;
if (overflow > 0)
{
rect_clamped.bottom -= overflow;
}
if (rect_clamped.bottom - rect_clamped.top <= 0)
return;
if (rect_clamped.right - rect_clamped.left <= 0)
return;
for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
{
unsigned char *destination_pointer = &surface->pixels[((rect_clamped.top + j) * surface->pitch) + (rect_clamped.left * 3)];
for (long i = 0; i < rect_clamped.right - rect_clamped.left; ++i)
{
*destination_pointer++ = red;
*destination_pointer++ = green;
*destination_pointer++ = blue;
}
}
}
Backend_Glyph* Backend_LoadGlyph(const unsigned char *pixels, unsigned int width, unsigned int height, int pitch)
{
Backend_Glyph *glyph = (Backend_Glyph*)malloc(sizeof(Backend_Glyph));
if (glyph == NULL)
return NULL;
glyph->pixels = (unsigned char*)malloc(width * height);
if (glyph->pixels == NULL)
{
free(glyph);
return NULL;
}
unsigned char *destination_pointer = glyph->pixels;
for (unsigned int y = 0; y < height; ++y)
memcpy(&glyph->pixels[y * width], &pixels[y * pitch], width);
glyph->width = width;
glyph->height = height;
return glyph;
}
void Backend_UnloadGlyph(Backend_Glyph *glyph)
{
if (glyph == NULL)
return;
free(glyph->pixels);
free(glyph);
}
void Backend_PrepareToDrawGlyphs(Backend_Surface *destination_surface, const unsigned char *colour_channels)
{
if (destination_surface == NULL)
return;
glyph_destination_surface = destination_surface;
memcpy(glyph_colour_channels, colour_channels, sizeof(glyph_colour_channels));
}
void Backend_DrawGlyph(Backend_Glyph *glyph, long x, long y)
{
if (glyph == NULL)
return;
for (unsigned int iy = MAX(-y, 0); y + iy < MIN(y + glyph->height, glyph_destination_surface->height); ++iy)
{
for (unsigned int ix = MAX(-x, 0); x + ix < MIN(x + glyph->width, glyph_destination_surface->width); ++ix)
{
const unsigned char alpha_int = glyph->pixels[iy * glyph->width + ix];
if (alpha_int != 0)
{
const float alpha = alpha_int / 255.0f;
unsigned char *bitmap_pixel = glyph_destination_surface->pixels + (y + iy) * glyph_destination_surface->pitch + (x + ix) * 3;
for (unsigned int j = 0; j < 3; ++j)
bitmap_pixel[j] = (unsigned char)((glyph_colour_channels[j] * alpha) + (bitmap_pixel[j] * (1.0f - alpha))); // Alpha blending
}
}
}
}
void Backend_FlushGlyphs(void)
{
}
void Backend_HandleRenderTargetLoss(void)
{
// No problem for us
}
void Backend_HandleWindowResize(void)
{
// https://wiki.libsdl.org/SDL_GetWindowSurface
// We need to fetch a new surface pointer
window_sdlsurface = SDL_GetWindowSurface(window);
}