mesh_drawable

Mesh stored on the GPU (VBOs, shader, texture, model transform), ready to be drawn.

module 16_drawablesource: mesh_drawable.hpp

2 functions take it 0 return it 0 operators

The GPU buffers filled once by initialize_data_on_gpu (one VBO per attribute), and the per-draw fields (shader, textures, model matrices, material) with the uniform each one is sent to by draw. Tap to enlarge.

initialize_data_on_gpu copies each array of the mesh into a GPU buffer. Tap to enlarge.

Fields and methods

Members of the struct mesh_drawable. Most of what you do with a CGP type goes through the free functions listed below.

Fields

`opengl_shader_structure default_shader`	Static shader shared by all mesh_drawable and used by default in initialize_data_on_gpu, loaded from shaders/mesh/mesh.vert.glsl and mesh.frag.glsl by the application.
`opengl_texture_image_structure default_texture`	Static 1x1 white RGBA texture shared by all mesh_drawable and used by default in initialize_data_on_gpu.
`opengl_shader_structure shader`	Shader program used to draw this drawable, which must be valid (non-zero id) at draw time.
`opengl_texture_image_structure texture`	Main texture bound to texture unit 0 and sent to the uniform image_texture at draw time.
`std::map<std::string,opengl_texture_image_structure> supplementary_texture`	Additional textures for multi-texturing, keyed by uniform name and bound to texture units 1, 2, ... in the order of the map at draw time.
`opengl_vbo_structure vbo_position`	VBO storing the vertex positions, bound to shader location 0.
`opengl_vbo_structure vbo_normal`	VBO storing the vertex normals, bound to shader location 1.
`opengl_vbo_structure vbo_color`	VBO storing the vertex colors, bound to shader location 2.
`opengl_vbo_structure vbo_uv`	VBO storing the vertex texture coordinates, bound to shader location 3.
`std::vector<opengl_vbo_structure> supplementary_vbo`	Optional extra VBOs (per-vertex or per-instance), where the element k is bound to shader location k+4.
`opengl_ebo_structure ebo_connectivity`	EBO storing the triangle indices used by the indexed draw call.
`GLuint vao = 0`	OpenGL id of the Vertex Array Object describing the VBO layout, 0 when not initialized.
`affine model`	Model transform of the drawable (translation, rotation, scaling, scaling_xyz), reset to identity by initialize_data_on_gpu and clear.
`affine_rts hierarchy_transform_model`	Global transform set by hierarchy_mesh_drawable::update_local_to_global_coordinates, applied first in the model matrix sent to the shader.
`mat4 supplementary_model_matrix = mat4::build_identity()`	Generic 4x4 matrix inserted between hierarchy_transform_model and model in the model matrix, identity by default and reset by initialize_data_on_gpu.
`material_mesh_drawable_phong material`	Phong material (color, alpha, shading coefficients, texture settings) sent to the uniform struct material at draw time.

Methods

`void initialize_data_on_gpu(mesh const& data, opengl_shader_structure const& shader = default_shader, opengl_texture_image_structure const& texture = default_texture)`	Checks the mesh with mesh_check, uploads its position, normal, color, uv and connectivity into new VBOs, an EBO and a VAO (locations 0 to 3), and resets model, material and supplementary_model_matrix, keeping a previously set shader or texture when the default one is passed. src
`void clear()`	Deletes the VBOs (including the supplementary ones), the EBO and the VAO, and resets shader, texture, supplementary_texture, model and material without deleting the shader program or the textures. src
`void send_opengl_uniform(bool expected = true) const`	Sends the uniform model = hierarchy_transform_model * supplementary_model_matrix * model and the material uniforms to the current shader. src
`void initialize_supplementary_data_on_gpu(numarray<T> const& data, GLuint location_index, GLuint divisor = 0)`	Uploads an extra vec2, vec3 or vec4 array into supplementary_vbo and binds it in the VAO at location_index (which must be at least 4), with divisor greater than 0 for per-instance data. src
`void update_supplementary_data_on_gpu(numarray<T> const& data, GLuint location_index, int size_elements_update = -1)`	Overwrites the content of the supplementary VBO at location_index (at least 4, already initialized) without reallocation, sending only the first size_elements_update elements when it is not -1. src

Functions taking a mesh_drawable

Draw 2

draw

source

void draw(
    mesh_drawable const& drawable,
    environment_generic_structure const& environment = environment_generic_structure(),
    int instance_count = 1,
    bool expected_uniforms = true,
    uniform_generic_structure const& additional_uniforms = uniform_generic_structure(),
    GLenum draw_mode = GL_TRIANGLES,
    material_mesh_drawable_phong const* material_override = nullptr
)

Draw a mesh_drawable with its shader, textures, model and material, plus the environment and optional additional uniforms, possibly instanced or with an overriding material.

draw_wireframe

source

void draw_wireframe(
    mesh_drawable const& drawable,
    environment_generic_structure const& environment = environment_generic_structure(),
    vec3 const& color = {0,0,1},
    int instance_count = 1,
    bool expected_uniforms = true,
    uniform_generic_structure const& additional_uniforms = uniform_generic_structure()
)

Draw the triangle edges of a mesh_drawable in a flat color, slightly offset toward the camera (no effect with Emscripten/WebGL).

Functions returning a mesh_drawable

None.

Operators

None.