[docs] Include uncompressed shader source in .cpp comments

This is meant to
(1) Make it easier for new developers to find the source
(2) Make it easier to look at shader diffs when the GL JS pin changes

1 files changed, 295 insertions, 0 deletions

diff --git a/src/mbgl/shaders/line_sdf.cpp b/src/mbgl/shaders/line_sdf.cpp
index ad8644a7d5..2573d9fd3f 100644
--- a/src/mbgl/shaders/line_sdf.cpp
+++ b/src/mbgl/shaders/line_sdf.cpp
@@ -10,5 +10,300 @@ const char* line_sdf::name = "line_sdf";
 const char* line_sdf::vertexSource = source() + 61204;
 const char* line_sdf::fragmentSource = source() + 66571;
 
+// Uncompressed source of line_sdf.vertex.glsl:
+/*
+// floor(127 / 2) == 63.0
+// the maximum allowed miter limit is 2.0 at the moment. the extrude normal is
+// stored in a byte (-128..127). we scale regular normals up to length 63, but
+// there are also "special" normals that have a bigger length (of up to 126 in
+// this case).
+// #define scale 63.0
+#define scale 0.015873016
+
+// We scale the distance before adding it to the buffers so that we can store
+// long distances for long segments. Use this value to unscale the distance.
+#define LINE_DISTANCE_SCALE 2.0
+
+// the distance over which the line edge fades out.
+// Retina devices need a smaller distance to avoid aliasing.
+#define ANTIALIASING 1.0 / DEVICE_PIXEL_RATIO / 2.0
+
+attribute vec4 a_pos_normal;
+attribute vec4 a_data;
+
+uniform mat4 u_matrix;
+uniform mediump float u_ratio;
+uniform vec2 u_patternscale_a;
+uniform float u_tex_y_a;
+uniform vec2 u_patternscale_b;
+uniform float u_tex_y_b;
+uniform vec2 u_gl_units_to_pixels;
+
+varying vec2 v_normal;
+varying vec2 v_width2;
+varying vec2 v_tex_a;
+varying vec2 v_tex_b;
+varying float v_gamma_scale;
+
+
+#ifndef HAS_UNIFORM_u_color
+uniform lowp float a_color_t;
+attribute highp vec4 a_color;
+varying highp vec4 color;
+#else
+uniform highp vec4 u_color;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_blur
+uniform lowp float a_blur_t;
+attribute lowp vec2 a_blur;
+varying lowp float blur;
+#else
+uniform lowp float u_blur;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_opacity
+uniform lowp float a_opacity_t;
+attribute lowp vec2 a_opacity;
+varying lowp float opacity;
+#else
+uniform lowp float u_opacity;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_gapwidth
+uniform lowp float a_gapwidth_t;
+attribute mediump vec2 a_gapwidth;
+#else
+uniform mediump float u_gapwidth;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_offset
+uniform lowp float a_offset_t;
+attribute lowp vec2 a_offset;
+#else
+uniform lowp float u_offset;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_width
+uniform lowp float a_width_t;
+attribute mediump vec2 a_width;
+varying mediump float width;
+#else
+uniform mediump float u_width;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_floorwidth
+uniform lowp float a_floorwidth_t;
+attribute lowp vec2 a_floorwidth;
+varying lowp float floorwidth;
+#else
+uniform lowp float u_floorwidth;
+#endif
+
+
+void main() {
+    
+#ifndef HAS_UNIFORM_u_color
+    color = unpack_mix_color(a_color, a_color_t);
+#else
+    highp vec4 color = u_color;
+#endif
+
+    
+#ifndef HAS_UNIFORM_u_blur
+    blur = unpack_mix_vec2(a_blur, a_blur_t);
+#else
+    lowp float blur = u_blur;
+#endif
+
+    
+#ifndef HAS_UNIFORM_u_opacity
+    opacity = unpack_mix_vec2(a_opacity, a_opacity_t);
+#else
+    lowp float opacity = u_opacity;
+#endif
+
+    
+#ifndef HAS_UNIFORM_u_gapwidth
+    mediump float gapwidth = unpack_mix_vec2(a_gapwidth, a_gapwidth_t);
+#else
+    mediump float gapwidth = u_gapwidth;
+#endif
+
+    
+#ifndef HAS_UNIFORM_u_offset
+    lowp float offset = unpack_mix_vec2(a_offset, a_offset_t);
+#else
+    lowp float offset = u_offset;
+#endif
+
+    
+#ifndef HAS_UNIFORM_u_width
+    width = unpack_mix_vec2(a_width, a_width_t);
+#else
+    mediump float width = u_width;
+#endif
+
+    
+#ifndef HAS_UNIFORM_u_floorwidth
+    floorwidth = unpack_mix_vec2(a_floorwidth, a_floorwidth_t);
+#else
+    lowp float floorwidth = u_floorwidth;
+#endif
+
+
+    vec2 a_extrude = a_data.xy - 128.0;
+    float a_direction = mod(a_data.z, 4.0) - 1.0;
+    float a_linesofar = (floor(a_data.z / 4.0) + a_data.w * 64.0) * LINE_DISTANCE_SCALE;
+
+    vec2 pos = a_pos_normal.xy;
+
+    // x is 1 if it's a round cap, 0 otherwise
+    // y is 1 if the normal points up, and -1 if it points down
+    mediump vec2 normal = a_pos_normal.zw;
+    v_normal = normal;
+
+    // these transformations used to be applied in the JS and native code bases.
+    // moved them into the shader for clarity and simplicity.
+    gapwidth = gapwidth / 2.0;
+    float halfwidth = width / 2.0;
+    offset = -1.0 * offset;
+
+    float inset = gapwidth + (gapwidth > 0.0 ? ANTIALIASING : 0.0);
+    float outset = gapwidth + halfwidth * (gapwidth > 0.0 ? 2.0 : 1.0) + (halfwidth == 0.0 ? 0.0 : ANTIALIASING);
+
+    // Scale the extrusion vector down to a normal and then up by the line width
+    // of this vertex.
+    mediump vec2 dist =outset * a_extrude * scale;
+
+    // Calculate the offset when drawing a line that is to the side of the actual line.
+    // We do this by creating a vector that points towards the extrude, but rotate
+    // it when we're drawing round end points (a_direction = -1 or 1) since their
+    // extrude vector points in another direction.
+    mediump float u = 0.5 * a_direction;
+    mediump float t = 1.0 - abs(u);
+    mediump vec2 offset2 = offset * a_extrude * scale * normal.y * mat2(t, -u, u, t);
+
+    vec4 projected_extrude = u_matrix * vec4(dist / u_ratio, 0.0, 0.0);
+    gl_Position = u_matrix * vec4(pos + offset2 / u_ratio, 0.0, 1.0) + projected_extrude;
+
+    // calculate how much the perspective view squishes or stretches the extrude
+    float extrude_length_without_perspective = length(dist);
+    float extrude_length_with_perspective = length(projected_extrude.xy / gl_Position.w * u_gl_units_to_pixels);
+    v_gamma_scale = extrude_length_without_perspective / extrude_length_with_perspective;
+
+    v_tex_a = vec2(a_linesofar * u_patternscale_a.x / floorwidth, normal.y * u_patternscale_a.y + u_tex_y_a);
+    v_tex_b = vec2(a_linesofar * u_patternscale_b.x / floorwidth, normal.y * u_patternscale_b.y + u_tex_y_b);
+
+    v_width2 = vec2(outset, inset);
+}
+
+*/
+
+// Uncompressed source of line_sdf.fragment.glsl:
+/*
+
+uniform sampler2D u_image;
+uniform float u_sdfgamma;
+uniform float u_mix;
+
+varying vec2 v_normal;
+varying vec2 v_width2;
+varying vec2 v_tex_a;
+varying vec2 v_tex_b;
+varying float v_gamma_scale;
+
+
+#ifndef HAS_UNIFORM_u_color
+varying highp vec4 color;
+#else
+uniform highp vec4 u_color;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_blur
+varying lowp float blur;
+#else
+uniform lowp float u_blur;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_opacity
+varying lowp float opacity;
+#else
+uniform lowp float u_opacity;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_width
+varying mediump float width;
+#else
+uniform mediump float u_width;
+#endif
+
+
+#ifndef HAS_UNIFORM_u_floorwidth
+varying lowp float floorwidth;
+#else
+uniform lowp float u_floorwidth;
+#endif
+
+
+void main() {
+    
+#ifdef HAS_UNIFORM_u_color
+    highp vec4 color = u_color;
+#endif
+
+    
+#ifdef HAS_UNIFORM_u_blur
+    lowp float blur = u_blur;
+#endif
+
+    
+#ifdef HAS_UNIFORM_u_opacity
+    lowp float opacity = u_opacity;
+#endif
+
+    
+#ifdef HAS_UNIFORM_u_width
+    mediump float width = u_width;
+#endif
+
+    
+#ifdef HAS_UNIFORM_u_floorwidth
+    lowp float floorwidth = u_floorwidth;
+#endif
+
+
+    // Calculate the distance of the pixel from the line in pixels.
+    float dist = length(v_normal) * v_width2.s;
+
+    // Calculate the antialiasing fade factor. This is either when fading in
+    // the line in case of an offset line (v_width2.t) or when fading out
+    // (v_width2.s)
+    float blur2 = (blur + 1.0 / DEVICE_PIXEL_RATIO) * v_gamma_scale;
+    float alpha = clamp(min(dist - (v_width2.t - blur2), v_width2.s - dist) / blur2, 0.0, 1.0);
+
+    float sdfdist_a = texture2D(u_image, v_tex_a).a;
+    float sdfdist_b = texture2D(u_image, v_tex_b).a;
+    float sdfdist = mix(sdfdist_a, sdfdist_b, u_mix);
+    alpha *= smoothstep(0.5 - u_sdfgamma / floorwidth, 0.5 + u_sdfgamma / floorwidth, sdfdist);
+
+    gl_FragColor = color * (alpha * opacity);
+
+#ifdef OVERDRAW_INSPECTOR
+    gl_FragColor = vec4(1.0);
+#endif
+}
+
+*/
+
 } // namespace shaders
 } // namespace mbgl