Merge pull request #67639 from clayjohn/GLES3-2d-shadows

Add 2D shadows and canvas SDF to OpenGL3 renderer

1 files changed, 205 insertions, 0 deletions

diff --git a/drivers/gles3/shaders/canvas_sdf.glsl b/drivers/gles3/shaders/canvas_sdf.glsl
new file mode 100644
index 0000000000..424ec22457
--- /dev/null
+++ b/drivers/gles3/shaders/canvas_sdf.glsl
@@ -0,0 +1,205 @@
+/* clang-format off */
+#[modes]
+
+mode_load = #define MODE_LOAD
+mode_load_shrink = #define MODE_LOAD_SHRINK
+mode_process = #define MODE_PROCESS
+mode_store = #define MODE_STORE
+mode_store_shrink = #define MODE_STORE_SHRINK
+
+#[specializations]
+
+#[vertex]
+
+layout(location = 0) in vec2 vertex_attrib;
+
+/* clang-format on */
+
+uniform ivec2 size;
+uniform int stride;
+uniform int shift;
+uniform ivec2 base_size;
+
+void main() {
+	gl_Position = vec4(vertex_attrib, 1.0, 1.0);
+}
+
+/* clang-format off */
+#[fragment]
+
+#define SDF_MAX_LENGTH 16384.0
+
+#if defined(MODE_LOAD) || defined(MODE_LOAD_SHRINK)
+uniform lowp sampler2D src_pixels;//texunit:0
+#else
+uniform highp isampler2D src_process;//texunit:0
+#endif
+
+uniform	ivec2 size;
+uniform	int stride;
+uniform	int shift;
+uniform	ivec2 base_size;
+
+#if defined(MODE_LOAD) || defined(MODE_LOAD_SHRINK) || defined(MODE_PROCESS)
+layout(location = 0) out ivec4 distance_field;
+#else
+layout(location = 0) out vec4 distance_field;
+#endif
+
+vec4 float_to_vec4(float p_float) {
+    highp vec4 comp = fract(p_float * vec4(255.0 * 255.0 * 255.0, 255.0 * 255.0, 255.0, 1.0));
+	comp -= comp.xxyz * vec4(0.0, 1.0 / 255.0, 1.0 / 255.0, 1.0 / 255.0);
+	return comp;
+}
+
+void main() {
+	ivec2 pos = ivec2(gl_FragCoord.xy);
+
+#ifdef MODE_LOAD
+
+	bool solid = texelFetch(src_pixels, pos, 0).r > 0.5;
+	distance_field = solid ? ivec4(ivec2(-32767), 0, 0) : ivec4(ivec2(32767), 0, 0);
+#endif
+
+#ifdef MODE_LOAD_SHRINK
+
+	int s = 1 << shift;
+	ivec2 base = pos << shift;
+	ivec2 center = base + ivec2(shift);
+
+	ivec2 rel = ivec2(32767);
+	float d = 1e20;
+	int found = 0;
+	int solid_found = 0;
+	for (int i = 0; i < s; i++) {
+		for (int j = 0; j < s; j++) {
+			ivec2 src_pos = base + ivec2(i, j);
+			if (any(greaterThanEqual(src_pos, base_size))) {
+				continue;
+			}
+			bool solid = texelFetch(src_pixels, src_pos, 0).r > 0.5;
+			if (solid) {
+				float dist = length(vec2(src_pos - center));
+				if (dist < d) {
+					d = dist;
+					rel = src_pos;
+				}
+				solid_found++;
+			}
+			found++;
+		}
+	}
+
+	if (solid_found == found) {
+		//mark solid only if all are solid
+		rel = ivec2(-32767);
+	}
+
+	distance_field = ivec4(rel, 0, 0);
+#endif
+
+#ifdef MODE_PROCESS
+
+	ivec2 base = pos << shift;
+	ivec2 center = base + ivec2(shift);
+
+	ivec2 rel = texelFetch(src_process, pos, 0).xy;
+
+	bool solid = rel.x < 0;
+
+	if (solid) {
+		rel = -rel - ivec2(1);
+	}
+
+	if (center != rel) {
+		//only process if it does not point to itself
+		const int ofs_table_size = 8;
+		const ivec2 ofs_table[ofs_table_size] = ivec2[](
+				ivec2(-1, -1),
+				ivec2(0, -1),
+				ivec2(+1, -1),
+
+				ivec2(-1, 0),
+				ivec2(+1, 0),
+
+				ivec2(-1, +1),
+				ivec2(0, +1),
+				ivec2(+1, +1));
+
+		float dist = length(vec2(rel - center));
+		for (int i = 0; i < ofs_table_size; i++) {
+			ivec2 src_pos = pos + ofs_table[i] * stride;
+			if (any(lessThan(src_pos, ivec2(0))) || any(greaterThanEqual(src_pos, size))) {
+				continue;
+			}
+			ivec2 src_rel = texelFetch(src_process, src_pos, 0).xy;
+			bool src_solid = src_rel.x < 0;
+			if (src_solid) {
+				src_rel = -src_rel - ivec2(1);
+			}
+
+			if (src_solid != solid) {
+				src_rel = ivec2(src_pos << shift); //point to itself if of different type
+			}
+
+			float src_dist = length(vec2(src_rel - center));
+			if (src_dist < dist) {
+				dist = src_dist;
+				rel = src_rel;
+			}
+		}
+	}
+
+	if (solid) {
+		rel = -rel - ivec2(1);
+	}
+
+	distance_field = ivec4(rel, 0, 0);
+#endif
+
+#ifdef MODE_STORE
+
+	ivec2 rel = texelFetch(src_process, pos, 0).xy;
+
+	bool solid = rel.x < 0;
+
+	if (solid) {
+		rel = -rel - ivec2(1);
+	}
+
+	float d = length(vec2(rel - pos));
+
+	if (solid) {
+		d = -d;
+	}
+
+	d /= SDF_MAX_LENGTH;
+	d = clamp(d, -1.0, 1.0);
+	distance_field = float_to_vec4(d*0.5+0.5);
+
+#endif
+
+#ifdef MODE_STORE_SHRINK
+
+	ivec2 base = pos << shift;
+	ivec2 center = base + ivec2(shift);
+
+	ivec2 rel = texelFetch(src_process, pos, 0).xy;
+
+	bool solid = rel.x < 0;
+
+	if (solid) {
+		rel = -rel - ivec2(1);
+	}
+
+	float d = length(vec2(rel - center));
+
+	if (solid) {
+		d = -d;
+	}
+	d /= SDF_MAX_LENGTH;
+	d = clamp(d, -1.0, 1.0);
+	distance_field = float_to_vec4(d*0.5+0.5);
+
+#endif
+}