fill drawing

src/geometry/fill_buffer.cpp

@@ -0,0 +1,71 @@
+#include <llmr/geometry/fill_buffer.hpp>
+#include <llmr/platform/gl.hpp>
+// #include <cmath>
+
+using namespace llmr;
+
+fill_buffer::fill_buffer()
+    : vertex_buffer(0),
+      element_buffer(0),
+      dirty(true) {
+
+}
+
+fill_buffer::~fill_buffer() {
+    if (vertex_buffer != 0) {
+        glDeleteBuffers(1, &vertex_buffer);
+        vertex_buffer = 0;
+    }
+    if (element_buffer != 0) {
+        glDeleteBuffers(1, &element_buffer);
+        element_buffer = 0;
+    }
+}
+
+uint32_t fill_buffer::vertex_length() const {
+    // We store 2 coordinates per vertex
+    return vertices.size() / 2;
+}
+
+uint32_t fill_buffer::elements_length() const {
+    // A triangle has 3 indices
+    return elements.size() / 3;
+}
+
+void fill_buffer::addDegenerate() {
+    vertices.push_back(32767);
+    vertices.push_back(0);
+}
+
+void fill_buffer::addCoordinate(int16_t x, int16_t y) {
+    vertices.push_back(x);
+    vertices.push_back(y);
+}
+
+void fill_buffer::addElements(uint16_t a, uint16_t b, uint16_t c) {
+    elements.push_back(a);
+    elements.push_back(b);
+    elements.push_back(c);
+}
+
+void fill_buffer::bind() {
+    if (vertex_buffer == 0) {
+        glGenBuffers(1, &vertex_buffer);
+        glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
+    } else {
+        glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
+    }
+
+    if (element_buffer == 0) {
+        glGenBuffers(1, &element_buffer);
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, element_buffer);
+    } else {
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, element_buffer);
+    }
+
+    if (dirty) {
+        glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(uint16_t), vertices.data(), GL_STATIC_DRAW);
+        glBufferData(GL_ELEMENT_ARRAY_BUFFER, elements.size() * sizeof(uint16_t), elements.data(), GL_STATIC_DRAW);
+        dirty = false;
+    }
+}