mkxp-z/shader/bitmapBlit.pgl.c
刘皓 2cd8202af3
Convert GLSL shaders to PortableGL's shader format
PortableGL supports shaders, but requires them to be compiled
ahead-of-time to C or C++.

I'll write a compiler later to translate from GLSL to this format
automatically at build time.
2025-03-13 16:16:17 -04:00

38 lines
1.7 KiB
C

#include "bitmapBlit.pgl.h"
void mkxpBitmapBlitVS(float *_output, pgl_vec4 *_attribs, Shader_Builtins *builtins, void *_uniforms)
{
struct BitmapBlitVarying *output = (struct BitmapBlitVarying *)_output;
struct BitmapBlitAttribs *attribs = (struct BitmapBlitAttribs *)_attribs;
struct BitmapBlitUniforms *uniforms = (struct BitmapBlitUniforms *)_uniforms;
pgl_vec2 pos = add_vec2s(attribs->position, uniforms->translation);
builtins->gl_Position = mult_mat4_vec4(uniforms->projMat, (pgl_vec4){pos.x, pos.y, 0, 1});
output->v_texCoord = mult_vec2s(attribs->texCoord, uniforms->texSizeInv);
}
void mkxpBitmapBlitFS(float *_input, Shader_Builtins *builtins, void *_uniforms)
{
struct BitmapBlitVarying *input = (struct BitmapBlitVarying *)_input;
struct BitmapBlitUniforms *uniforms = (struct BitmapBlitUniforms *)_uniforms;
pgl_vec2 coor = input->v_texCoord;
pgl_vec2 dstCoor = mult_vec2s(sub_vec2s(coor, (pgl_vec2){uniforms->subRect.x, uniforms->subRect.y}), (pgl_vec2){uniforms->subRect.z, uniforms->subRect.w});
pgl_vec4 srcFrag = mkxp_pgl_texture2D(uniforms->source, coor.x, coor.y);
pgl_vec4 dstFrag = mkxp_pgl_texture2D(uniforms->destination, dstCoor.x, dstCoor.y);
pgl_vec4 resFrag;
float co1 = srcFrag.w * uniforms->opacity;
float co2 = dstFrag.w * (1.0 - co1);
resFrag.w = co1 + co2;
if (resFrag.w == 0.0) {
resFrag.x = srcFrag.x;
resFrag.y = srcFrag.y;
resFrag.z = srcFrag.z;
} else {
pgl_vec3 frag = add_vec3s((pgl_vec3){co1*srcFrag.x, co1*srcFrag.y, co1*srcFrag.z}, (pgl_vec3){co2*dstFrag.x, co2*dstFrag.y, co2*dstFrag.z});
resFrag.x = frag.x / resFrag.w;
resFrag.y = frag.y / resFrag.w;
resFrag.z = frag.z / resFrag.w;
}
builtins->gl_FragColor = resFrag;
}