105 lines
2.4 KiB
GLSL
105 lines
2.4 KiB
GLSL
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in vec4 gl_FragCoord;
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#request uniform "screen" screen
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uniform ivec2 screen; /* screen dimensions */
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#request uniform "prev" tex
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uniform sampler2D tex; /* screen texture */
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out vec4 fragment; /* output */
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#include "@graph.glsl"
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#include ":graph.glsl"
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#if ANTI_ALIAS == 0
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#error __disablestage
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#endif
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/* Moves toward the border of the graph, gives the
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y coordinate of the last colored pixel */
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float get_col_height_up(float x, float oy) {
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float y = oy;
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#if INVERT > 0
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while (y >= 0) {
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#else
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while (y < screen.y) {
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#endif
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vec4 f = texelFetch(tex, ivec2(x, y), 0);
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if (f.a <= 0) {
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#if INVERT > 0
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y += 1;
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#else
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y -= 1;
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#endif
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break;
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}
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#if INVERT > 0
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y -= 1;
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#else
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y += 1;
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#endif
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}
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return y;
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}
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/* Moves toward the base of the graph, gives the
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y coordinate of the first colored pixel */
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float get_col_height_down(float x, float oy) {
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float y = oy;
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#if INVERT > 0
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while (y < screen.y) {
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#else
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while (y >= 0) {
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#endif
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vec4 f = texelFetch(tex, ivec2(x, y), 0);
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if (f.a > 0) {
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break;
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}
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#if INVERT > 0
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y += 1;
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#else
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y -= 1;
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#endif
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}
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return y;
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}
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void main() {
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fragment = texelFetch(tex, ivec2(gl_FragCoord.x, gl_FragCoord.y), 0);
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#if ANTI_ALIAS > 0
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if (fragment.a <= 0) {
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bool left_done = false;
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float h2;
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float a_fact = 0;
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if (texelFetch(tex, ivec2(gl_FragCoord.x - 1, gl_FragCoord.y), 0).a > 0) {
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float h1 = get_col_height_up(gl_FragCoord.x - 1, gl_FragCoord.y);
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h2 = get_col_height_down(gl_FragCoord.x, gl_FragCoord.y);
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fragment = texelFetch(tex, ivec2(gl_FragCoord.x, h2), 0);
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a_fact = clamp(abs((h1 - gl_FragCoord.y) / (h2 - h1)), 0.0, 1.0);
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left_done = true;
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}
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if (texelFetch(tex, ivec2(gl_FragCoord.x + 1, gl_FragCoord.y), 0).a > 0) {
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if (!left_done) {
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h2 = get_col_height_down(gl_FragCoord.x, gl_FragCoord.y);
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fragment = texelFetch(tex, ivec2(gl_FragCoord.x, h2), 0);
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}
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float h3 = get_col_height_up(gl_FragCoord.x + 1, gl_FragCoord.y);
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a_fact = max(a_fact, clamp(abs((h3 - gl_FragCoord.y) / (h2 - h3)), 0.0, 1.0));
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}
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fragment.a *= a_fact;
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}
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#endif
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}
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