Remove requirement to have vertex positions when creating a mesh. Meshes can now be constructed from an index buffer alone

5 files changed, 22 insertions, 21 deletions

diff --git a/drivers/gles3/rasterizer_scene_gles3.cpp b/drivers/gles3/rasterizer_scene_gles3.cpp
index 3e416bc615..9bbe960d86 100644
--- a/drivers/gles3/rasterizer_scene_gles3.cpp
+++ b/drivers/gles3/rasterizer_scene_gles3.cpp
@@ -867,7 +867,6 @@ void RasterizerSceneGLES3::_update_sky_radiance(RID p_env, const Projection &p_p
 		GLES3::MaterialStorage::get_singleton()->shaders.sky_shader.version_set_uniform(SkyShaderGLES3::TIME, time, shader_data->version, SkyShaderGLES3::MODE_CUBEMAP);
 		GLES3::MaterialStorage::get_singleton()->shaders.sky_shader.version_set_uniform(SkyShaderGLES3::PROJECTION, cm.matrix[2][0], cm.matrix[0][0], cm.matrix[2][1], cm.matrix[1][1], shader_data->version, SkyShaderGLES3::MODE_CUBEMAP);
 
-		// Bind a vertex array or else OpenGL complains. We won't actually use it
 		glBindVertexArray(sky_globals.screen_triangle_array);
 
 		glViewport(0, 0, sky->radiance_size, sky->radiance_size);
@@ -2150,7 +2149,9 @@ void RasterizerSceneGLES3::_render_list_template(RenderListParameters *p_params,
 		index_array_gl = mesh_storage->mesh_surface_get_index_buffer(mesh_surface, surf->lod_index);
 
 		if (prev_vertex_array_gl != vertex_array_gl) {
-			glBindVertexArray(vertex_array_gl);
+			if (vertex_array_gl != 0) {
+				glBindVertexArray(vertex_array_gl);
+			}
 			prev_vertex_array_gl = vertex_array_gl;
 		}
 
diff --git a/drivers/gles3/storage/material_storage.cpp b/drivers/gles3/storage/material_storage.cpp
index 26441fc726..5ed5ec51b9 100644
--- a/drivers/gles3/storage/material_storage.cpp
+++ b/drivers/gles3/storage/material_storage.cpp
@@ -1450,8 +1450,8 @@ MaterialStorage::MaterialStorage() {
 		actions.renames["UV2"] = "uv2_interp";
 		actions.renames["COLOR"] = "color_interp";
 		actions.renames["POINT_SIZE"] = "gl_PointSize";
-		actions.renames["INSTANCE_ID"] = "gl_InstanceIndex";
-		actions.renames["VERTEX_ID"] = "gl_VertexIndex";
+		actions.renames["INSTANCE_ID"] = "gl_InstanceID";
+		actions.renames["VERTEX_ID"] = "gl_VertexID";
 
 		actions.renames["ALPHA_SCISSOR_THRESHOLD"] = "alpha_scissor_threshold";
 		actions.renames["ALPHA_HASH_SCALE"] = "alpha_hash_scale";
diff --git a/drivers/gles3/storage/mesh_storage.cpp b/drivers/gles3/storage/mesh_storage.cpp
index dee715150b..38de0220e3 100644
--- a/drivers/gles3/storage/mesh_storage.cpp
+++ b/drivers/gles3/storage/mesh_storage.cpp
@@ -186,11 +186,13 @@ void MeshStorage::mesh_add_surface(RID p_mesh, const RS::SurfaceData &p_surface)
 	s->format = p_surface.format;
 	s->primitive = p_surface.primitive;
 
-	glGenBuffers(1, &s->vertex_buffer);
-	glBindBuffer(GL_ARRAY_BUFFER, s->vertex_buffer);
-	glBufferData(GL_ARRAY_BUFFER, p_surface.vertex_data.size(), p_surface.vertex_data.ptr(), (s->format & RS::ARRAY_FLAG_USE_DYNAMIC_UPDATE) ? GL_DYNAMIC_DRAW : GL_STATIC_DRAW);
-	glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
-	s->vertex_buffer_size = p_surface.vertex_data.size();
+	if (p_surface.vertex_data.size()) {
+		glGenBuffers(1, &s->vertex_buffer);
+		glBindBuffer(GL_ARRAY_BUFFER, s->vertex_buffer);
+		glBufferData(GL_ARRAY_BUFFER, p_surface.vertex_data.size(), p_surface.vertex_data.ptr(), (s->format & RS::ARRAY_FLAG_USE_DYNAMIC_UPDATE) ? GL_DYNAMIC_DRAW : GL_STATIC_DRAW);
+		glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
+		s->vertex_buffer_size = p_surface.vertex_data.size();
+	}
 
 	if (p_surface.attribute_data.size()) {
 		glGenBuffers(1, &s->attribute_buffer);
@@ -214,7 +216,7 @@ void MeshStorage::mesh_add_surface(RID p_mesh, const RS::SurfaceData &p_surface)
 	}
 
 	if (p_surface.index_count) {
-		bool is_index_16 = p_surface.vertex_count <= 65536;
+		bool is_index_16 = p_surface.vertex_count <= 65536 && p_surface.vertex_count > 0;
 		glGenBuffers(1, &s->index_buffer);
 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, s->index_buffer);
 		glBufferData(GL_ELEMENT_ARRAY_BUFFER, p_surface.index_data.size(), p_surface.index_data.ptr(), GL_STATIC_DRAW);
@@ -238,6 +240,8 @@ void MeshStorage::mesh_add_surface(RID p_mesh, const RS::SurfaceData &p_surface)
 		}
 	}
 
+	ERR_FAIL_COND_MSG(!p_surface.index_count && !p_surface.vertex_count, "Meshes must contain a vertex array, an index array, or both");
+
 	s->aabb = p_surface.aabb;
 	s->bone_aabbs = p_surface.bone_aabbs; //only really useful for returning them.
 
@@ -340,7 +344,9 @@ RS::SurfaceData MeshStorage::mesh_get_surface(RID p_mesh, int p_surface) const {
 
 	RS::SurfaceData sd;
 	sd.format = s.format;
-	sd.vertex_data = Utilities::buffer_get_data(GL_ARRAY_BUFFER, s.vertex_buffer, s.vertex_buffer_size);
+	if (s.vertex_buffer != 0) {
+		sd.vertex_data = Utilities::buffer_get_data(GL_ARRAY_BUFFER, s.vertex_buffer, s.vertex_buffer_size);
+	}
 
 	if (s.attribute_buffer != 0) {
 		sd.attribute_data = Utilities::buffer_get_data(GL_ARRAY_BUFFER, s.attribute_buffer, s.attribute_buffer_size);
diff --git a/drivers/gles3/storage/mesh_storage.h b/drivers/gles3/storage/mesh_storage.h
index 339380b3b0..74f5800795 100644
--- a/drivers/gles3/storage/mesh_storage.h
+++ b/drivers/gles3/storage/mesh_storage.h
@@ -75,7 +75,7 @@ struct Mesh {
 		// Cache vertex arrays so they can be created
 		struct Version {
 			uint32_t input_mask = 0;
-			GLuint vertex_array;
+			GLuint vertex_array = 0;
 
 			Attrib attribs[RS::ARRAY_MAX];
 		};
@@ -92,7 +92,7 @@ struct Mesh {
 			float edge_length = 0.0;
 			uint32_t index_count = 0;
 			uint32_t index_buffer_size = 0;
-			GLuint index_buffer;
+			GLuint index_buffer = 0;
 		};
 
 		LOD *lods = nullptr;
@@ -175,7 +175,7 @@ struct MultiMesh {
 	bool *data_cache_dirty_regions = nullptr;
 	uint32_t data_cache_used_dirty_regions = 0;
 
-	GLuint buffer;
+	GLuint buffer = 0;
 
 	bool dirty = false;
 	MultiMesh *dirty_list = nullptr;
@@ -362,7 +362,7 @@ public:
 	_FORCE_INLINE_ GLenum mesh_surface_get_index_type(void *p_surface) const {
 		Mesh::Surface *s = reinterpret_cast<Mesh::Surface *>(p_surface);
 
-		return s->vertex_count <= 65536 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT;
+		return (s->vertex_count <= 65536 && s->vertex_count > 0) ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT;
 	}
 
 	// Use this to cache Vertex Array Objects so they are only generated once
diff --git a/drivers/vulkan/rendering_device_vulkan.cpp b/drivers/vulkan/rendering_device_vulkan.cpp
index bcb6092d87..2debba1b83 100644
--- a/drivers/vulkan/rendering_device_vulkan.cpp
+++ b/drivers/vulkan/rendering_device_vulkan.cpp
@@ -7805,12 +7805,6 @@ void RenderingDeviceVulkan::draw_list_draw(DrawListID p_list, bool p_use_indices
 		ERR_FAIL_COND_MSG(!dl->validation.index_array_size,
 				"Draw command requested indices, but no index buffer was set.");
 
-		if (dl->validation.pipeline_vertex_format != INVALID_ID) {
-			// Uses vertices, do some vertex validations.
-			ERR_FAIL_COND_MSG(dl->validation.vertex_array_size < dl->validation.index_array_max_index,
-					"Index array references (max index: " + itos(dl->validation.index_array_max_index) + ") indices beyond the vertex array size (" + itos(dl->validation.vertex_array_size) + ").");
-		}
-
 		ERR_FAIL_COND_MSG(dl->validation.pipeline_uses_restart_indices != dl->validation.index_buffer_uses_restart_indices,
 				"The usage of restart indices in index buffer does not match the render primitive in the pipeline.");
 #endif