Implement the count parameter in RenderingServer.canvas_item_add_triangle_array()

doc/classes/RenderingServer.xml

@@ -410,7 +410,7 @@
 			<param index="8" name="count" type="int" default="-1" />
 			<description>
 				Draws a triangle array on the [CanvasItem] pointed to by the [param item] [RID]. This is internally used by [Line2D] and [StyleBoxFlat] for rendering. [method canvas_item_add_triangle_array] is highly flexible, but more complex to use than [method canvas_item_add_polygon].
-				[b]Note:[/b] [param count] is unused and can be left unspecified.
+				[b]Note:[/b] If [param count] is set to a non-negative value, only the first [code]count * 3[/code] indices (corresponding to [code skip-lint]count[/code] triangles) will be drawn. Otherwise, all indices are drawn.
 			</description>
 		</method>
 		<method name="canvas_item_attach_skeleton">

drivers/gles3/rasterizer_canvas_gles3.cpp

@@ -2424,7 +2424,7 @@ void RasterizerCanvasGLES3::reset_canvas() {
 void RasterizerCanvasGLES3::draw_lens_distortion_rect(const Rect2 &p_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample) {
 }
 
-RendererCanvasRender::PolygonID RasterizerCanvasGLES3::request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs, const Vector<int> &p_bones, const Vector<float> &p_weights) {
+RendererCanvasRender::PolygonID RasterizerCanvasGLES3::request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs, const Vector<int> &p_bones, const Vector<float> &p_weights, int p_count) {
 	// We interleave the vertex data into one big VBO to improve cache coherence
 	uint32_t vertex_count = p_points.size();
 	uint32_t stride = 2;
@@ -2552,15 +2552,15 @@ RendererCanvasRender::PolygonID RasterizerCanvasGLES3::request_polygon(const Vec
 	if (p_indices.size()) {
 		//create indices, as indices were requested
 		Vector<uint8_t> index_buffer;
-		index_buffer.resize(p_indices.size() * sizeof(int32_t));
+		index_buffer.resize(p_count * sizeof(int32_t));
 		{
 			uint8_t *w = index_buffer.ptrw();
-			memcpy(w, p_indices.ptr(), sizeof(int32_t) * p_indices.size());
+			memcpy(w, p_indices.ptr(), sizeof(int32_t) * p_count);
 		}
 		glGenBuffers(1, &pb.index_buffer);
 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, pb.index_buffer);
-		GLES3::Utilities::get_singleton()->buffer_allocate_data(GL_ELEMENT_ARRAY_BUFFER, pb.index_buffer, p_indices.size() * 4, index_buffer.ptr(), GL_STATIC_DRAW, "Polygon 2D index buffer");
-		pb.count = p_indices.size();
+		GLES3::Utilities::get_singleton()->buffer_allocate_data(GL_ELEMENT_ARRAY_BUFFER, pb.index_buffer, p_count * 4, index_buffer.ptr(), GL_STATIC_DRAW, "Polygon 2D index buffer");
+		pb.count = p_count;
 	}
 
 	glBindVertexArray(0);

drivers/gles3/rasterizer_canvas_gles3.h

@@ -200,7 +200,7 @@ public:
 		PolygonID last_id = 0;
 	} polygon_buffers;
 
-	RendererCanvasRender::PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>()) override;
+	RendererCanvasRender::PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>(), int p_count = -1) override;
 	void free_polygon(PolygonID p_polygon) override;
 
 	struct InstanceData {

servers/rendering/dummy/rasterizer_canvas_dummy.h

@@ -34,7 +34,7 @@
 
 class RasterizerCanvasDummy : public RendererCanvasRender {
 public:
-	PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>()) override { return 0; }
+	PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>(), int p_count = -1) override { return 0; }
 	void free_polygon(PolygonID p_polygon) override {}
 
 	void canvas_render_items(RID p_to_render_target, Item *p_item_list, const Color &p_modulate, Light *p_light_list, Light *p_directional_list, const Transform2D &p_canvas_transform, RS::CanvasItemTextureFilter p_default_filter, RS::CanvasItemTextureRepeat p_default_repeat, bool p_snap_2d_vertices_to_pixel, bool &r_sdf_used, RenderingMethod::RenderInfo *r_render_info = nullptr) override {}

servers/rendering/renderer_canvas_cull.cpp

@@ -1735,7 +1735,7 @@ void RendererCanvasCull::canvas_item_add_triangle_array(RID p_item, const Vector
 
 	polygon->texture = p_texture;
 
-	polygon->polygon.create(p_indices, p_points, p_colors, p_uvs, p_bones, p_weights);
+	polygon->polygon.create(p_indices, p_points, p_colors, p_uvs, p_bones, p_weights, p_count);
 
 	polygon->primitive = RS::PRIMITIVE_TRIANGLES;
 }

servers/rendering/renderer_canvas_render.h

@@ -130,7 +130,7 @@ public:
 	//easier wrap to avoid mistakes
 
 	typedef uint64_t PolygonID;
-	virtual PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>()) = 0;
+	virtual PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>(), int p_count = -1) = 0;
 	virtual void free_polygon(PolygonID p_polygon) = 0;
 
 	//also easier to wrap to avoid mistakes
@@ -138,8 +138,10 @@ public:
 		PolygonID polygon_id;
 		Rect2 rect_cache;
 
-		_FORCE_INLINE_ void create(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>()) {
+		_FORCE_INLINE_ void create(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>(), int p_count = -1) {
 			ERR_FAIL_COND(polygon_id != 0);
+			int count = p_count < 0 ? p_indices.size() : p_count * 3;
+			ERR_FAIL_COND(count > p_indices.size());
 			{
 				uint32_t pc = p_points.size();
 				const Vector2 *v2 = p_points.ptr();
@@ -148,7 +150,7 @@ public:
 					rect_cache.expand_to(v2[i]);
 				}
 			}
-			polygon_id = singleton->request_polygon(p_indices, p_points, p_colors, p_uvs, p_bones, p_weights);
+			polygon_id = singleton->request_polygon(p_indices, p_points, p_colors, p_uvs, p_bones, p_weights, count);
 		}
 
 		_FORCE_INLINE_ Polygon() { polygon_id = 0; }

servers/rendering/renderer_rd/renderer_canvas_render_rd.cpp

@@ -100,7 +100,7 @@ void RendererCanvasRenderRD::_update_transform_to_mat4(const Transform3D &p_tran
 	p_mat4[15] = 1;
 }
 
-RendererCanvasRender::PolygonID RendererCanvasRenderRD::request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs, const Vector<int> &p_bones, const Vector<float> &p_weights) {
+RendererCanvasRender::PolygonID RendererCanvasRenderRD::request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs, const Vector<int> &p_bones, const Vector<float> &p_weights, int p_count) {
 	// Care must be taken to generate array formats
 	// in ways where they could be reused, so we will
 	// put single-occurring elements first, and repeated
@@ -311,14 +311,14 @@ RendererCanvasRender::PolygonID RendererCanvasRenderRD::request_polygon(const Ve
 	if (p_indices.size()) {
 		//create indices, as indices were requested
 		Vector<uint8_t> index_buffer;
-		index_buffer.resize(p_indices.size() * sizeof(int32_t));
+		index_buffer.resize(p_count * sizeof(int32_t));
 		{
 			uint8_t *w = index_buffer.ptrw();
 			memcpy(w, p_indices.ptr(), sizeof(int32_t) * p_indices.size());
 		}
-		pb.index_buffer = RD::get_singleton()->index_buffer_create(p_indices.size(), RD::INDEX_BUFFER_FORMAT_UINT32, index_buffer);
-		pb.indices = RD::get_singleton()->index_array_create(pb.index_buffer, 0, p_indices.size());
-		pb.primitive_count = p_indices.size();
+		pb.index_buffer = RD::get_singleton()->index_buffer_create(p_count, RD::INDEX_BUFFER_FORMAT_UINT32, index_buffer);
+		pb.indices = RD::get_singleton()->index_array_create(pb.index_buffer, 0, p_count);
+		pb.primitive_count = p_count;
 	}
 
 	pb.vertex_format_id = vertex_id;

servers/rendering/renderer_rd/renderer_canvas_render_rd.h

@@ -638,7 +638,7 @@ class RendererCanvasRenderRD : public RendererCanvasRender {
 	void _update_occluder_buffer(uint32_t p_size);
 
 public:
-	PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>()) override;
+	PolygonID request_polygon(const Vector<int> &p_indices, const Vector<Point2> &p_points, const Vector<Color> &p_colors, const Vector<Point2> &p_uvs = Vector<Point2>(), const Vector<int> &p_bones = Vector<int>(), const Vector<float> &p_weights = Vector<float>(), int p_count = -1) override;
 	void free_polygon(PolygonID p_polygon) override;
 
 	RID light_create() override;