Added DrawRoundedRect()

src/raylib.h

@@ -1056,6 +1056,7 @@ RLAPI void DrawRectangleGradientH(int posX, int posY, int width, int height, Col
 RLAPI void DrawRectangleGradientEx(Rectangle rec, Color col1, Color col2, Color col3, Color col4);       // Draw a gradient-filled rectangle with custom vertex colors
 RLAPI void DrawRectangleLines(int posX, int posY, int width, int height, Color color);                   // Draw rectangle outline
 RLAPI void DrawRectangleLinesEx(Rectangle rec, int lineThick, Color color);                              // Draw rectangle outline with extended parameters
+RLAPI void DrawRoundedRect(Rectangle rec, float roundness, int segments, Color color);  // Draw rectangle with rounded edges
 RLAPI void DrawTriangle(Vector2 v1, Vector2 v2, Vector2 v3, Color color);                                // Draw a color-filled triangle
 RLAPI void DrawTriangleLines(Vector2 v1, Vector2 v2, Vector2 v3, Color color);                           // Draw triangle outline
 RLAPI void DrawPoly(Vector2 center, int sides, float radius, float rotation, Color color);               // Draw a regular polygon (Vector version)

src/shapes.c

@@ -698,6 +698,200 @@ void DrawRectangleLinesEx(Rectangle rec, int lineThick, Color color)
     DrawRectangle( (int)rec.x, (int)(rec.y + lineThick), lineThick, (int)(rec.height - lineThick*2), color);
 }
 
+// Draw rectangle with rounded edges.
+void DrawRoundedRect(Rectangle rec, float roundness, int segments, Color color)
+{
+    // Not a rounded rectangle
+    // NOTE: Make sure we have at least 1px space left to render the rectangles near the corners
+    if(roundness <= 0.0f || rec.width <= 1 || rec.height <= 1 )
+    {
+        DrawRectangleRec(rec, color);
+        return;
+    }
+    
+    if(roundness >= 1.0f) roundness = 1.0f;
+    
+    // Calculate corner radius
+    // NOTE: Make sure we have at least 1px space left to render the rectangles near the corners
+    float radius = rec.width > rec.height ? ((rec.height-1)*roundness)/2 : ((rec.width-1)*roundness)/2;
+    if(radius <= 0.0f) return;
+    
+    // Calculate number of segments to use for the corners
+    if (segments < 4)
+    {
+        // Calculate how many segments we need to draw a smooth circle, taken from https://stackoverflow.com/a/2244088
+        #ifndef CIRCLE_ERROR_RATE
+        #define CIRCLE_ERROR_RATE  0.5f
+        #endif
+        // Calculate the maximum angle between segments based on the error rate.
+        float th = acosf(2*powf(1 - CIRCLE_ERROR_RATE/radius, 2) - 1);
+        segments = ceilf(2*PI/th)/4;
+        if (segments <= 0) segments = 4;
+    }
+    
+    float stepLength = 90.0f/(float)segments;
+    
+    /*  Quick sketch to make sense of all of this (there are 9 parts to draw, also mark the 12 points we'll use below)
+     *  Not my best attempt at ASCII art, just preted it's a rounded rectangle :)
+     *     P0                    P1
+     *       ____________________
+     *     /|                    |\
+     *    /1|          2         |3\
+     *P7 /__|____________________|__\ P2
+     *  |   |P8                P9|   |
+     *  | 8 |          9         | 4 |
+     *  | __|____________________|__ |
+     *P6 \  |P11              P10|  / P3
+     *    \7|          6         |5/
+     *     \|____________________|/
+     *     P5                    P4
+     */
+     
+    const Vector2 point[12] = { // coordinates of the 12 points that define the rounded rect (the idea here is to make things easier)
+        {(float)rec.x + radius, rec.y}, {(float)(rec.x + rec.width) - radius, rec.y}, { rec.x + rec.width, (float)rec.y + radius }, // PO, P1, P2
+        {rec.x + rec.width, (float)(rec.y + rec.height) - radius}, {(float)(rec.x + rec.width) - radius, rec.y + rec.height}, // P3, P4
+        {(float)rec.x + radius, rec.y + rec.height}, { rec.x, (float)(rec.y + rec.height) - radius}, {rec.x, (float)rec.y + radius}, // P5, P6, P7
+        {(float)rec.x + radius, (float)rec.y + radius}, {(float)(rec.x + rec.width) - radius, (float)rec.y + radius}, // P8, P9
+        {(float)(rec.x + rec.width) - radius, (float)(rec.y + rec.height) - radius}, {(float)rec.x + radius, (float)(rec.y + rec.height) - radius} // P10, P11
+    };
+
+#if defined(SUPPORT_QUADS_DRAW_MODE)
+    if (rlCheckBufferLimit(16*segments/2 + 5*4)) rlglDraw();
+    
+    rlBegin(RL_QUADS);
+        // Draw all of the 4 corners: [1] Upper Left Corner, [3] Upper Right Corner, [5] Lower Right Corner, [7] Lower Left Corner 
+        const Vector2 centers[4] = { point[8], point[9], point[10], point[11] };
+        const float angles[4] = {180.0f, 90.0f, 0.0f, 270.0f };
+        for(int k = 0; k < 4; ++k) // Hope the compiler is smart enough to unroll this loop
+        {
+            float angle = angles[k];
+            const Vector2 center = centers[k];
+            // NOTE: Every QUAD actually represents two segments
+            for (int i = 0; i < segments/2; i++)
+            {
+                rlColor4ub(color.r, color.g, color.b, color.a);
+                rlVertex2f(center.x, center.y);
+                rlVertex2f(center.x + sinf(DEG2RAD*angle)*radius, center.y + cosf(DEG2RAD*angle)*radius);
+                rlVertex2f(center.x + sinf(DEG2RAD*(angle + stepLength))*radius, center.y + cosf(DEG2RAD*(angle + stepLength))*radius);
+                rlVertex2f(center.x + sinf(DEG2RAD*(angle + stepLength*2))*radius, center.y + cosf(DEG2RAD*(angle + stepLength*2))*radius);
+                angle += (stepLength*2);
+            }
+            // NOTE: In case number of segments is odd, we add one last piece to the cake
+            if (segments%2)
+            {
+                rlColor4ub(color.r, color.g, color.b, color.a);
+                rlVertex2f(center.x, center.y);
+                rlVertex2f(center.x + sinf(DEG2RAD*angle)*radius, center.y + cosf(DEG2RAD*angle)*radius);
+                rlVertex2f(center.x + sinf(DEG2RAD*(angle + stepLength))*radius, center.y + cosf(DEG2RAD*(angle + stepLength))*radius);
+                rlVertex2f(center.x, center.y);
+            }
+        }
+        
+        // [2] Upper Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[0].x, point[0].y);
+        rlVertex2f(point[8].x, point[8].y);
+        rlVertex2f(point[9].x, point[9].y);
+        rlVertex2f(point[1].x, point[1].y);
+        
+        // [4] Right Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[2].x, point[2].y);
+        rlVertex2f(point[9].x, point[9].y);
+        rlVertex2f(point[10].x, point[10].y);
+        rlVertex2f(point[3].x, point[3].y);
+        
+        // [6] Bottom Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[5].x, point[5].y);
+        rlVertex2f(point[4].x, point[4].y);
+        rlVertex2f(point[10].x, point[10].y);
+        
+        // [8] Left Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[7].x, point[7].y);
+        rlVertex2f(point[6].x, point[6].y);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[8].x, point[8].y);
+        
+        // [9] Middle Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[8].x, point[8].y);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[10].x, point[10].y);
+        rlVertex2f(point[9].x, point[9].y);
+        
+    rlEnd();
+#else
+    if (rlCheckBufferLimit(12*segments + 5*6)) rlglDraw(); // 4 corners with 3 vertices per segment + 5 rectangles with 6 vertices each
+    
+    rlBegin(RL_TRIANGLES);
+        // Draw all of the 4 corners: [1] Upper Left Corner, [3] Upper Right Corner, [5] Lower Right Corner, [7] Lower Left Corner 
+        const Vector2 centers[4] = { point[8], point[9], point[10], point[11] };
+        const float angles[4] = {180.0f, 90.0f, 0.0f, 270.0f };
+        for(int k = 0; k < 4; ++k) // Hope the compiler is smart enough to unroll this loop
+        {
+            float angle = angles[k];
+            const Vector2 center = centers[k];
+            for (int i = 0; i < segments; i++)
+            {
+                rlColor4ub(color.r, color.g, color.b, color.a);
+                rlVertex2f(center.x, center.y);
+                rlVertex2f(center.x + sinf(DEG2RAD*angle)*radius, center.y + cosf(DEG2RAD*angle)*radius);
+                rlVertex2f(center.x + sinf(DEG2RAD*(angle + stepLength))*radius, center.y + cosf(DEG2RAD*(angle + stepLength))*radius);
+                angle += stepLength;
+            }
+        }
+
+        // [2] Upper Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[0].x, point[0].y);
+        rlVertex2f(point[8].x, point[8].y);
+        rlVertex2f(point[9].x, point[9].y);
+        rlVertex2f(point[1].x, point[1].y);
+        rlVertex2f(point[0].x, point[0].y);
+        rlVertex2f(point[9].x, point[9].y);
+        
+        // [4] Right Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[9].x, point[9].y);
+        rlVertex2f(point[10].x, point[10].y);
+        rlVertex2f(point[3].x, point[3].y);
+        rlVertex2f(point[2].x, point[2].y);
+        rlVertex2f(point[9].x, point[9].y);
+        rlVertex2f(point[3].x, point[3].y);
+        
+        // [6] Bottom Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[5].x, point[5].y);
+        rlVertex2f(point[4].x, point[4].y);
+        rlVertex2f(point[10].x, point[10].y);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[4].x, point[4].y);
+        
+        // [8] Left Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[7].x, point[7].y);
+        rlVertex2f(point[6].x, point[6].y);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[8].x, point[8].y);
+        rlVertex2f(point[7].x, point[7].y);
+        rlVertex2f(point[11].x, point[11].y);
+        
+        // [9] Middle Rectangle
+        rlColor4ub(color.r, color.g, color.b, color.a);
+        rlVertex2f(point[8].x, point[8].y);
+        rlVertex2f(point[11].x, point[11].y);
+        rlVertex2f(point[10].x, point[10].y);
+        rlVertex2f(point[9].x, point[9].y);
+        rlVertex2f(point[8].x, point[8].y);
+        rlVertex2f(point[10].x, point[10].y);
+    rlEnd();
+#endif
+}
+
 // Draw a triangle
 void DrawTriangle(Vector2 v1, Vector2 v2, Vector2 v3, Color color)
 {