stuff

TexturePainter.h

@@ -0,0 +1,71 @@
+#ifndef TEXTURE_PAINTER_CLASS
+#define TEXTURE_PAINTER_CLASS
+
+#include <cmath>
+
+#include <glm/glm.hpp>
+
+#include "texture.h"
+
+// The brush behind the texture drawer. Edits a Texture's pixels and uploads them.
+class TexturePainter {
+public:
+    glm::vec3 color = glm::vec3(0.0f);
+    int brushSize = 8;   // radius in pixels of a 256 wide texture, so it looks the same on any size
+
+    // uv runs 0-1 from the top left of the image. Joins up with the last call until EndStroke.
+    void Stroke(Texture& texture, const glm::vec2& uv) {
+        const glm::vec2 point(uv.x * texture.width, (1.0f - uv.y) * texture.height);
+        const float radius = glm::max(1.0f, brushSize * texture.width / 256.0f);
+
+        if (!stroking) {
+            Stamp(texture, point, radius);
+        }
+        else {
+            // Fill the gap, the mouse can cross a lot of pixels in one frame
+            const int steps = (int)std::ceil(glm::length(point - lastPoint) / (radius * 0.5f));
+            for (int i = 1; i <= steps; i++)
+                Stamp(texture, glm::mix(lastPoint, point, (float)i / (float)steps), radius);
+        }
+
+        stroking = true;
+        lastPoint = point;
+        texture.Upload();
+    }
+
+    void EndStroke() {
+        stroking = false;
+    }
+
+    void Clear(Texture& texture) {
+        texture.pixels.assign(texture.pixels.size(), 255);
+        texture.Upload();
+    }
+
+private:
+    bool stroking = false;
+    glm::vec2 lastPoint = glm::vec2(0.0f);
+
+    void Stamp(Texture& texture, const glm::vec2& center, float radius) {
+        const int minX = glm::max((int)(center.x - radius), 0);
+        const int maxX = glm::min((int)(center.x + radius), texture.width - 1);
+        const int minY = glm::max((int)(center.y - radius), 0);
+        const int maxY = glm::min((int)(center.y + radius), texture.height - 1);
+
+        for (int y = minY; y <= maxY; y++) {
+            for (int x = minX; x <= maxX; x++) {
+                const glm::vec2 offset = glm::vec2(x + 0.5f, y + 0.5f) - center;
+                if (glm::dot(offset, offset) > radius * radius)
+                    continue;
+
+                unsigned char* pixel = &texture.pixels[((size_t)y * texture.width + x) * 4];
+                pixel[0] = (unsigned char)(color.r * 255.0f);
+                pixel[1] = (unsigned char)(color.g * 255.0f);
+                pixel[2] = (unsigned char)(color.b * 255.0f);
+                pixel[3] = 255;
+            }
+        }
+    }
+};
+
+#endif