gistfile1.txt

            float3 drawTopArea(float2 uv)
            {
                float3 color = FOREGROUND_COLOR;

                float areaWidth = 1.0 - FRAME_MARGIN * 2;
                float areaHeight = 0.35;
                float boxWidth = areaWidth / 4.0;

                for (uint i = 0; i < 4; i++)
                {
                    float boxHeight = 0.25 + sin(_Time.y * 2.0 + float(i) * 0.5) * 0.1;
                    float leftCornerRadius = i == 0 ? CORNER_RADIUS : 0.0;
                    float rightCornerRadius = i == 3 ? CORNER_RADIUS : 0.0;

                    float boxDist = sdRoundedBoxBottomRight(
                        translate(uv, float2(boxWidth * i, areaHeight)),
                        float2(boxWidth, boxHeight),
                        float4(rightCornerRadius, CORNER_RADIUS, leftCornerRadius, CORNER_RADIUS)
                    );
                    float shellDist = shell(boxDist, OUTLINE_WIDTH);

                    // outer shell
                    addElement(color, ACTIVE_COLOR, shellDist);

                    // colored inner portion
                    float3 innerColor = float4x4(
                        float4(1.0, 0.0, 0.0, 0.0), // red
                        float4(1.0, 1.0, 0.0, 0.0), // yellow
                        float4(0.0, 1.0, 0.0, 0.0), // green
                        float4(0.0, 0.0, 1.0, 0.0)  // blue
                    )[i % 4] * 0.4;
                    addElement(color, innerColor, boxDist+OUTLINE_WIDTH);

                    // Top pivot
                    float handleDist = sdSphere(
                        translate(uv, float2(boxWidth * 0.5 + boxWidth * i, areaHeight-boxHeight)),
                        HANDLE_RADIUS
                    );
                    addElement(color, 1.0, handleDist);
                }

                return color;
            }

            float3 drawGainSlider(float2 uv)
            {
                float3 color = FOREGROUND_COLOR;

                float areaWidth = 0.6; // these should probaby be passed in instead
                float areaHeight = 0.15;

                // Background fill
                float maxTriangleWidth = areaWidth*0.8;
                float bgTriangleDist = inflate(sdTriangleIsosceles(
                    rotate(translate(uv, float2(0.05, areaHeight * 0.5)), UNITY_PI*0.5), 
                    float2(areaHeight*0.3, maxTriangleWidth)
                ), 0.002);
                addElement(color, INACTIVE_COLOR, bgTriangleDist);

                // Current active area
                float currentTriangleWidth = maxTriangleWidth * (sin(_Time.y) * 0.5 + 0.5);
                float currentTriangleDist = max(bgTriangleDist, uv.x - currentTriangleWidth - 0.05);
                addElement(color, ACTIVE_COLOR, currentTriangleDist);

                // Slider handle
                float handleDist = sdSphere(
                    translate(uv, float2(currentTriangleWidth + 0.05, areaHeight * 0.5)),
                    HANDLE_RADIUS
                );
                addElement(color, ACTIVE_COLOR, handleDist);

                // Slider vertical grip
                float gripDist = abs(uv.x - currentTriangleWidth - 0.05) - OUTLINE_WIDTH;
                addElement(color, ACTIVE_COLOR, gripDist);

                return color;
            }

            float3 drawUI(float2 uv)
            {
                float3 color = BACKGROUND_COLOR;

                // Top area
                float2 topAreaOrigin = translate(uv, FRAME_MARGIN);
                float topAreaDist = sdRoundedBoxTopLeft(
                    topAreaOrigin,
                    float2(1.0 - FRAME_MARGIN * 2, 0.35),
                    CORNER_RADIUS
                );
                addElement(color, drawTopArea(topAreaOrigin), topAreaDist);

                // Gain slider
                float2 gainSliderOrigin = translate(uv, FRAME_MARGIN + float2(0, 0.4));
                float gainSliderDist = sdRoundedBoxTopLeft(
                    gainSliderOrigin,
                    float2(0.6, 0.15),
                    CORNER_RADIUS
                );
                addElement(color, drawGainSlider(gainSliderOrigin), gainSliderDist);

                return color;
            }