summaryrefslogtreecommitdiffstats
path: root/res/effectlib/distancefieldtext_dropshadow.vert
diff options
context:
space:
mode:
Diffstat (limited to 'res/effectlib/distancefieldtext_dropshadow.vert')
-rw-r--r--res/effectlib/distancefieldtext_dropshadow.vert88
1 files changed, 88 insertions, 0 deletions
diff --git a/res/effectlib/distancefieldtext_dropshadow.vert b/res/effectlib/distancefieldtext_dropshadow.vert
new file mode 100644
index 0000000..5939a8c
--- /dev/null
+++ b/res/effectlib/distancefieldtext_dropshadow.vert
@@ -0,0 +1,88 @@
+#ifdef GL_OES_standard_derivatives
+# extension GL_OES_standard_derivatives : enable
+#else
+# define use_fallback
+#endif
+
+uniform highp mat4 mvp;
+uniform highp float fontScale;
+uniform int textureWidth;
+uniform int textureHeight;
+uniform highp vec2 shadowOffset;
+
+attribute highp vec3 vCoord;
+attribute highp vec2 tCoord;
+attribute highp vec4 textureBounds;
+
+varying highp vec2 sampleCoord;
+varying highp vec2 shadowSampleCoord;
+varying highp vec4 normalizedTextureBounds;
+
+#ifdef use_fallback
+varying highp vec2 alphas;
+
+highp float thresholdFunc(highp float scale)
+{
+ highp float base = 0.5;
+ highp float baseDev = 0.065;
+ highp float devScaleMin = 0.15;
+ highp float devScaleMax = 0.3;
+ return base - ((clamp(scale, devScaleMin, devScaleMax) - devScaleMin)
+ / (devScaleMax - devScaleMin) * -baseDev + baseDev);
+}
+
+highp float spreadFunc(highp float scale)
+{
+ return 0.06 / scale;
+}
+
+highp vec2 alphaRange(highp float scale)
+{
+ highp float base = thresholdFunc(scale);
+ highp float range = spreadFunc(scale);
+ highp float alphaMin = max(0.0, base - range);
+ highp float alphaMax = min(base + range, 1.0);
+ return vec2(alphaMin, alphaMax);
+}
+
+highp float determinantOfSubmatrix(highp mat4 m, int col0, int col1, int row0, int row1)
+{
+ return m[col0][row0] * m[col1][row1] - m[col0][row1] * m[col1][row0];
+}
+
+highp float determinantOfSubmatrix(highp mat4 m, int col0, int col1, int col2,
+ int row0, int row1, int row2)
+{
+ highp float det = m[col0][row0] * determinantOfSubmatrix(m, col1, col2, row1, row2);
+ det -= m[col1][row0] * determinantOfSubmatrix(m, col0, col2, row1, row2);
+ det += m[col2][row0] * determinantOfSubmatrix(m, col0, col1, row1, row2);
+ return det;
+}
+
+highp float determinant(highp mat4 m)
+{
+ highp float det = m[0][0] * determinantOfSubmatrix(m, 1, 2, 3, 1, 2, 3);
+ det -= m[1][0] * determinantOfSubmatrix(m, 0, 2, 3, 1, 2, 3);
+ det += m[2][0] * determinantOfSubmatrix(m, 0, 1, 3, 1, 2, 3);
+ det -= m[3][0] * determinantOfSubmatrix(m, 0, 1, 2, 1, 2, 3);
+ return det;
+}
+#endif
+
+void main()
+{
+#ifdef use_fallback
+ highp float scale = fontScale * pow(abs(determinant(mvp)), 1.0 / 3.0);
+ alphas = alphaRange(scale);
+#endif
+
+ highp vec2 textureSizeMultiplier = vec2(1.0 / float(textureWidth),
+ 1.0 / float(textureHeight));
+
+ sampleCoord = tCoord * textureSizeMultiplier;
+ shadowSampleCoord = (tCoord - shadowOffset) * textureSizeMultiplier;
+ normalizedTextureBounds = vec4(textureBounds.xy * textureSizeMultiplier,
+ textureBounds.zw * textureSizeMultiplier);
+
+ gl_Position = mvp * vec4(vCoord, 1.0);
+}