add <image ...> atlases support

src/graphics/core/Batch2D.cpp

@@ -39,6 +39,7 @@ void Batch2D::setPrimitive(DrawPrimitive primitive) {
 void Batch2D::begin(){
     currentTexture = nullptr;
     blank->bind();
+    region = blank->getUVRegion();
     color = glm::vec4(1.0f);
     primitive = DrawPrimitive::triangle;
 }
@@ -50,8 +51,8 @@ void Batch2D::vertex(
 ) {
     buffer[index++] = x;
     buffer[index++] = y;
-    buffer[index++] = u;
-    buffer[index++] = v;
+    buffer[index++] = u * region.getWidth() + region.u1;
+    buffer[index++] = v * region.getHeight() + region.v1;
     buffer[index++] = r;
     buffer[index++] = g;
     buffer[index++] = b;
@@ -64,8 +65,8 @@ void Batch2D::vertex(
 ) {
     buffer[index++] = point.x;
     buffer[index++] = point.y;
-    buffer[index++] = uvpoint.x;
-    buffer[index++] = uvpoint.y;
+    buffer[index++] = uvpoint.x * region.getWidth() + region.u1;
+    buffer[index++] = uvpoint.y * region.getHeight() + region.v1;
     buffer[index++] = r;
     buffer[index++] = g;
     buffer[index++] = b;
@@ -80,8 +81,10 @@ void Batch2D::texture(Texture* new_texture){
     currentTexture = new_texture;
     if (new_texture == nullptr) {
         blank->bind();
+        region = blank->getUVRegion();
     } else {
         new_texture->bind();
+        region = currentTexture->getUVRegion();
     }
 }
 
@@ -89,6 +92,10 @@ void Batch2D::untexture() {
     texture(nullptr);
 }
 
+void Batch2D::setRegion(UVRegion region) {
+    this->region = region;
+}
+
 void Batch2D::point(float x, float y, float r, float g, float b, float a){
     if (index + 6*B2D_VERTEX_SIZE >= capacity)
         flush();