Add vgerRadialGradient

audulus · May 29, 2024 · f07edd8 · f07edd8
1 parent b1c53a9
commit f07edd8
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Showing 6 changed files with 96 additions and 8 deletions.
diff --git a/Sources/vger/include/vger.h b/Sources/vger/include/vger.h
@@ -214,6 +214,15 @@ vgerPaintIndex vgerLinearGradient(vgerContext vg,
                                   vector_float4 outerColor,
                                   float glow);
 
+/// Create a paint for a linear gradient. Returns paint index. Paints are cleared each frame.
+vgerPaintIndex vgerRadialGradient(vgerContext vg,
+                                  vector_float2 center,
+                                  float         innerRadius,
+                                  float         outerRadius,
+                                  vector_float4 innerColor,
+                                  vector_float4 outerColor,
+                                  float glow);
+
 /// Create a paint using a texture image. Returns paint index. Paints are cleared each frame.
 vgerPaintIndex vgerImagePattern(vgerContext vg,
                                 vector_float2 origin,

diff --git a/Sources/vger/paint.h b/Sources/vger/paint.h
@@ -4,8 +4,16 @@
 
 #include "metal_compat.h"
 
+enum vgerPaintType {
+    vgerPaintTypeLinearGradient,
+    vgerPaintTypeRadialGradient,
+    vgerPaintTypeImagePattern,
+};
+
 struct vgerPaint {
 
+    vgerPaintType type;
+
 #ifdef __METAL_VERSION__
     float3x3 xform;
 #else
@@ -16,6 +24,12 @@ struct vgerPaint {
 
     float4 outerColor;
 
+    /// Inner radius for radial gradients.
+    float innerRadius;
+
+    /// Inner radius for radial gradients.
+    float outerRadius;
+
     /// Render into the glow layer?
     float glow;
 
@@ -29,12 +43,19 @@ struct vgerPaint {
 
 inline float4 applyPaint(const DEVICE vgerPaint& paint, float2 p) {
 
-    float d = clamp((paint.xform * float3{p.x, p.y, 1.0}).x, 0.0, 1.0);
-
-#ifdef __METAL_VERSION__
-    return mix(paint.innerColor, paint.outerColor, d);
-#else
-    return simd_mix(paint.innerColor, paint.outerColor, d);
-#endif
+    switch (paint.type) {
+        case vgerPaintTypeLinearGradient:
+        {
+            float d = clamp((paint.xform * float3{p.x, p.y, 1.0}).x, 0.0, 1.0);
+            return mix(paint.innerColor, paint.outerColor, d);
+        }
+        case vgerPaintTypeRadialGradient:
+        {
+            float d = clamp(length( (paint.xform * float3{p.x, p.y, 1.0}).xy), paint.innerRadius, paint.outerRadius);
+            return mix(paint.innerColor, paint.outerColor, (d-paint.innerRadius) / (paint.outerRadius - paint.innerRadius));
+        }
+        default:
+            return 0;
+    }
 
 }
diff --git a/Sources/vger/vger.mm b/Sources/vger/vger.mm
@@ -939,6 +939,7 @@ void vgerSetLayer(vgerContext vg, int layer) {
 vgerPaintIndex vgerColorPaint(vgerContext vg, float4 color) {
 
     vgerPaint p;
+    p.type = vgerPaintTypeLinearGradient;
     p.xform = matrix_identity_float3x3;
     p.innerColor = color;
     p.outerColor = color;
@@ -959,6 +960,16 @@ vgerPaintIndex vgerLinearGradient(vgerContext vg,
 
 }
 
+vgerPaintIndex vgerRadialGradient(vgerContext vg,
+                                  vector_float2 center,
+                                  float         innerRadius,
+                                  float         outerRadius,
+                                  vector_float4 innerColor,
+                                  vector_float4 outerColor,
+                                  float glow) {
+    return vg->addPaint(makeRadialGradient(center, innerRadius, outerRadius, innerColor, outerColor, glow));
+}
+
 vgerPaintIndex vgerImagePattern(vgerContext vg,
                                 float2 origin,
                                 float2 size,

diff --git a/Sources/vger/vger_private.h b/Sources/vger/vger_private.h
@@ -185,6 +185,7 @@ inline vgerPaint makeLinearGradient(float2 start,
                                     float glow) {
 
     vgerPaint p;
+    p.type = vgerPaintTypeLinearGradient;
 
     // Calculate transform aligned to the line
     float2 d = end - start;
@@ -206,6 +207,32 @@ inline vgerPaint makeLinearGradient(float2 start,
     return p;
 }
 
+inline vgerPaint makeRadialGradient(float2 center,
+                                    float  innerRadius,
+                                    float  outerRadius,
+                                    float4 innerColor,
+                                    float4 outerColor,
+                                    float glow) {
+
+    vgerPaint p;
+    p.type = vgerPaintTypeRadialGradient;
+
+    p.xform = inverse(float3x3{
+        float3{1, 0, 0},
+        float3{0, 1, 0},
+        float3{center.x, center.y, 1}
+    });
+
+    p.innerRadius = innerRadius;
+    p.outerRadius = outerRadius;
+    p.innerColor = innerColor;
+    p.outerColor = outerColor;
+    p.image = -1;
+    p.glow = glow;
+
+    return p;
+}
+
 inline vgerPaint makeImagePattern(float2 origin,
                                   float2 size,
                                   float angle,
@@ -214,6 +241,7 @@ inline vgerPaint makeImagePattern(float2 origin,
                                   float alpha) {
 
     vgerPaint p;
+    p.type  = vgerPaintTypeImagePattern;
     p.image = image.index;
     p.flipY = flipY;
 

diff --git a/Tests/vgerTests/images/vger_basics.png b/Tests/vgerTests/images/vger_basics.png
diff --git a/Tests/vgerTests/vgerTests.mm b/Tests/vgerTests/vgerTests.mm
@@ -117,7 +117,7 @@ static void SplitBezier(float t,
 }
 
 - (void) testSizes {
-    XCTAssertEqual(sizeof(vgerPaint), 96);
+    XCTAssertEqual(sizeof(vgerPaint), 128);
     XCTAssertEqual(sizeof(vgerPrim), 96);
 }
 
@@ -137,6 +137,7 @@ - (void) testBasic {
     vgerFillCircle(vg, float2{256, 256}, 40, cyan);
     vgerStrokeBezier(vg, {{256,256}, {256,384}, {384,384}}, 1, white);
     vgerFillRect(vg, float2{400,100}, float2{450,150}, 10, vgerLinearGradient(vg, float2{400,100}, float2{450, 150}, float4{0,1,1,1}, float4{1,0,1,1}, 0));
+    vgerFillRect(vg, float2{400,200}, float2{450,250}, 10, vgerRadialGradient(vg, float2{425,225}, 10, 40, float4{0,1,1,1}, float4{1,0,1,1}, 0));
     vgerStrokeArc(vg, float2{100,400}, 30, 3, theta, ap, white);
     vgerStrokeSegment(vg, float2{100,100}, float2{200,200}, 10, magenta);
     vgerStrokeRect(vg, float2{400,100}, float2{450,150}, 10, 2.0, magenta);
@@ -553,6 +554,24 @@ - (void) testPaint {
     v = p.xform * float3{20,20,1};
     XCTAssertTrue(equal(v, float3{1,1,1}));
 
+    p = makeRadialGradient(float2(0), 0, 1, float4(0), float4(1), 0);
+
+    XCTAssertTrue(equal(applyPaint(p, float2{0,0}), float4(0)));
+    XCTAssertTrue(equal(applyPaint(p, float2{1,0}), float4(1)));
+    XCTAssertTrue(equal(applyPaint(p, float2{0,1}), float4(1)));
+    XCTAssertTrue(equal(applyPaint(p, float2{-1,0}), float4(1)));
+    XCTAssertTrue(equal(applyPaint(p, float2{0,-1}), float4(1)));
+    XCTAssertTrue(equal(applyPaint(p, float2{1,1}), float4(1)));
+
+    p = makeRadialGradient(float2{1,0}, 0, 1, float4(0), float4(1), 0);
+    XCTAssertTrue(equal(applyPaint(p, float2{1,0}), float4(0)));
+    XCTAssertTrue(equal(applyPaint(p, float2{1,1}), float4(1)));
+
+    p = makeRadialGradient(float2{425,225}, 10, 40, float4{0,1,1,1}, float4{1,0,1,1}, 0);
+
+    c = applyPaint(p, float2{425,225});
+    XCTAssertTrue(equal(c, float4{0,1,1,1}));
+
 }
 
 - (void) testTextAlgin {