ref: 83e8320d84837fef22005bdf22535c5132c4d6b1
dir: /src/Backends/Rendering/Software.cpp/
#include "../Rendering.h"
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include "../Misc.h"
#include "Window/Software.h"
#include "../../Attributes.h"
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
typedef struct RenderBackend_Surface
{
unsigned char *pixels;
size_t width;
size_t height;
size_t pitch;
} RenderBackend_Surface;
typedef struct RenderBackend_GlyphAtlas
{
unsigned char *pixels;
size_t width;
size_t height;
} RenderBackend_GlyphAtlas;
static RenderBackend_Surface framebuffer;
static RenderBackend_GlyphAtlas *glyph_atlas;
static RenderBackend_Surface *glyph_destination_surface;
static unsigned char glyph_colour_channels[3];
RenderBackend_Surface* RenderBackend_Init(const char *window_title, size_t screen_width, size_t screen_height, bool fullscreen)
{
if (WindowBackend_Software_CreateWindow(window_title, screen_width, screen_height, fullscreen))
{
framebuffer.pixels = WindowBackend_Software_GetFramebuffer(&framebuffer.pitch);
framebuffer.width = screen_width;
framebuffer.height = screen_height;
return &framebuffer;
}
else
{
Backend_PrintError("Failed to create window");
}
return NULL;
}
void RenderBackend_Deinit(void)
{
WindowBackend_Software_DestroyWindow();
}
void RenderBackend_DrawScreen(void)
{
WindowBackend_Software_Display();
// Backends may use double-buffering, so fetch a new framebuffer just in case
framebuffer.pixels = WindowBackend_Software_GetFramebuffer(&framebuffer.pitch);
}
RenderBackend_Surface* RenderBackend_CreateSurface(size_t width, size_t height, bool render_target)
{
(void)render_target;
RenderBackend_Surface *surface = (RenderBackend_Surface*)malloc(sizeof(RenderBackend_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 RenderBackend_FreeSurface(RenderBackend_Surface *surface)
{
free(surface->pixels);
free(surface);
}
bool RenderBackend_IsSurfaceLost(RenderBackend_Surface *surface)
{
(void)surface;
return false;
}
void RenderBackend_RestoreSurface(RenderBackend_Surface *surface)
{
(void)surface;
}
void RenderBackend_UploadSurface(RenderBackend_Surface *surface, const unsigned char *pixels, size_t width, size_t height)
{
for (size_t y = 0; y < height; ++y)
memcpy(&surface->pixels[y * surface->pitch], &pixels[y * width * 3], width * 3);
}
ATTRIBUTE_HOT void RenderBackend_Blit(RenderBackend_Surface *source_surface, const RenderBackend_Rect *rect, RenderBackend_Surface *destination_surface, long x, long y, bool colour_key)
{
RenderBackend_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)
{
const 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 (UNLIKELY(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
{
const unsigned char *source_pointer = &source_surface->pixels[(rect_clamped.top * source_surface->pitch) + (rect_clamped.left * 3)];
unsigned char *destination_pointer = &destination_surface->pixels[(y * destination_surface->pitch) + (x * 3)];
for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
{
memcpy(destination_pointer, source_pointer, (rect_clamped.right - rect_clamped.left) * 3);
source_pointer += source_surface->pitch;
destination_pointer += destination_surface->pitch;
}
}
}
ATTRIBUTE_HOT void RenderBackend_ColourFill(RenderBackend_Surface *surface, const RenderBackend_Rect *rect, unsigned char red, unsigned char green, unsigned char blue)
{
RenderBackend_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;
}
}
}
RenderBackend_GlyphAtlas* RenderBackend_CreateGlyphAtlas(size_t width, size_t height)
{
RenderBackend_GlyphAtlas *atlas = (RenderBackend_GlyphAtlas*)malloc(sizeof(RenderBackend_GlyphAtlas));
if (atlas != NULL)
{
atlas->pixels = (unsigned char*)malloc(width * height);
if (atlas->pixels != NULL)
{
atlas->width = width;
atlas->height = height;
return atlas;
}
free(atlas);
}
return NULL;
}
void RenderBackend_DestroyGlyphAtlas(RenderBackend_GlyphAtlas *atlas)
{
free(atlas->pixels);
free(atlas);
}
void RenderBackend_UploadGlyph(RenderBackend_GlyphAtlas *atlas, size_t x, size_t y, const unsigned char *pixels, size_t width, size_t height, size_t pitch)
{
for (size_t i = 0; i < height; ++i)
memcpy(&atlas->pixels[(y + i) * atlas->width + x], &pixels[i * pitch], width);
}
void RenderBackend_PrepareToDrawGlyphs(RenderBackend_GlyphAtlas *atlas, RenderBackend_Surface *destination_surface, unsigned char red, unsigned char green, unsigned char blue)
{
glyph_atlas = atlas;
glyph_destination_surface = destination_surface;
glyph_colour_channels[0] = red;
glyph_colour_channels[1] = green;
glyph_colour_channels[2] = blue;
}
void RenderBackend_DrawGlyph(long x, long y, size_t glyph_x, size_t glyph_y, size_t glyph_width, size_t glyph_height)
{
size_t surface_x;
size_t surface_y;
// Clamp to within the destination surface's boundaries
if (x < 0)
{
surface_x = -x;
if (surface_x >= glyph_width)
return; // Glyph is offscreen to the left
glyph_x += surface_x;
glyph_width -= surface_x;
}
else
{
surface_x = x;
}
if (surface_x >= glyph_destination_surface->width)
return; // Glyph is offscreen to the right
if (glyph_width >= glyph_destination_surface->width - surface_x)
glyph_width = glyph_destination_surface->width - surface_x;
if (y < 0)
{
surface_y = -y;
if (surface_y >= glyph_height)
return; // Glyph is offscreen to the top
glyph_y += surface_y;
glyph_height -= surface_y;
}
else
{
surface_y = y;
}
if (surface_y >= glyph_destination_surface->height)
return; // Glyph is offscreen to the bottom
if (glyph_height >= glyph_destination_surface->height - surface_y)
glyph_height = glyph_destination_surface->height - surface_y;
// Do the actual drawing
for (size_t iy = 0; iy < glyph_height; ++iy)
{
for (size_t ix = 0; ix < glyph_width; ++ix)
{
const unsigned char alpha_int = glyph_atlas->pixels[(glyph_y + iy) * glyph_atlas->width + (glyph_x + ix)];
if (alpha_int != 0)
{
const float alpha = alpha_int / 255.0f;
unsigned char *bitmap_pixel = &glyph_destination_surface->pixels[(surface_y + iy) * glyph_destination_surface->pitch + (surface_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 RenderBackend_HandleRenderTargetLoss(void)
{
// No problem for us
}
void RenderBackend_HandleWindowResize(size_t width, size_t height)
{
WindowBackend_Software_HandleWindowResize(width, height);
}