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graphics_utils.c
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graphics_utils.c
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#include "core/graphics_utils.h"
#include "core/geometry.h"
#include "log.h"
#include <stdlib.h>
void apply_composite_operation(int composite_op) {
int sfactor, dfactor;
switch (composite_op) {
case source_atop:
sfactor = GL_DST_ALPHA;
dfactor = GL_ONE_MINUS_SRC_ALPHA;
break;
case source_in:
sfactor = GL_DST_ALPHA;
dfactor = GL_ZERO;
break;
case source_out:
sfactor = GL_ONE_MINUS_DST_ALPHA;
dfactor = GL_ZERO;
break;
case source_over:
sfactor = GL_ONE;
dfactor = GL_ONE_MINUS_SRC_ALPHA;
break;
case destination_atop:
sfactor = GL_DST_ALPHA;
dfactor = GL_SRC_ALPHA;
break;
case destination_in:
sfactor = GL_ZERO;
dfactor = GL_SRC_ALPHA;
break;
case destination_out:
sfactor = GL_ONE_MINUS_SRC_ALPHA;
dfactor = GL_ONE_MINUS_SRC_ALPHA;
break;
case destination_over:
sfactor = GL_DST_ALPHA;
dfactor = GL_SRC_ALPHA;
break;
case lighter:
sfactor = GL_ONE;
dfactor = GL_ONE;
break;
case x_or:
case copy:
default:
sfactor = GL_ONE;
dfactor = GL_ONE_MINUS_SRC_ALPHA;
break;
}
glEnable(GL_BLEND);
glBlendFunc(sfactor, dfactor);
}
//redraw read pixels
//apply the blendfunc
void set_up_full_compositing(context_2d *ctx, int x, int y, int width, int height, int composite_op) {
//clear the 4 rect's around the area
LOG("SETUP %i %i %i %i", x, y, ctx->width, height);
rect_2d top_rect = {0, 0, ctx->width, y};
rect_2d left_rect = {0, 0, x, ctx->height};
rect_2d bot_rect = {0, y + height, ctx->width, ctx->height - (y + height)};
rect_2d right_rect = {x + width, 0, ctx->width - (x + width), ctx->height};
context_2d_clearRect(ctx, &top_rect);
context_2d_clearRect(ctx, &left_rect);
context_2d_clearRect(ctx, &bot_rect);
context_2d_clearRect(ctx, &right_rect);
}
bool is_full_canvas_composite_operation(int composite_op) {
return (composite_op == source_in || composite_op == source_out ||
composite_op == destination_in || composite_op == destination_atop);
}