lg_render.c File Reference

Functions
int	lg_mesh_to_drawelements_cmd (LG_Mesh *mesh, int u_tex, LG_DrawElements_Cmd *draw_params)
void	lg_draw_elements (LG_DrawElements_Cmd *draw_params)
void	lg_drawelements_info (LG_DrawElements_Cmd *draw_params)
LG_Texture *	lg_dummy_texture ()

Detailed Description

 === Structs and wrapper funcs to efficiently draw mesh data ===

 - Set textures and params to be used by glDrawElements()
 - Make batch calls to glDrawElements()

 LG_DrawElements_Cmd = glDrawElements() command

Function Documentation

lg_mesh_to_drawelements_cmd()

int lg_mesh_to_drawelements_cmd	(	LG_Mesh *	mesh,
		int	u_tex,
		LG_DrawElements_Cmd *	draw_params
	)

Here we use:

• mesh->n_usemtl = num of 'usemtl' tags in OBJ file
• mesh->n_mat = num of 'newmtl'/'map_K' tags (materials with referenced textures) in MTL file
• mesh->materials[N_MAT_MAX] = materials 'lib'
• mesh->i_mat_in_vbo[N_USEMTL_MAX] = material face indices in VBO, referenced by 'usemtl' tags
• mesh->i_mat_in_lib[N_MAT_MAX] = texture indices in materials[N_MAT_MAX]

to compute size and shift

LG_N_MAX_DRAWS = N_USEMTL_MAX

Parameters

mesh	Pointer to a LG_Mesh struct
u_tex	Texture coords uniform to be used by glUniform1i()
draw_params	Pointer to a LG_DrawElements_Cmd struct

Returns

LG_OK if OK

lg_draw_elements()

void lg_draw_elements

(

LG_DrawElements_Cmd *

draw_params

)

Call glDrawElements(GL_TRIANGLES, size[i], GL_UNSIGNED_INT, shift[i]) n_draws times

Parameters

draw_params

Pointer to a LG_DrawElements_Cmd struct

lg_drawelements_info()

void lg_drawelements_info

(

LG_DrawElements_Cmd *

draw_params

)

Print out LG_DrawElements_Cmd info

Parameters

draw_params

Pointer to a LG_DrawElements_Cmd struct

lg_dummy_texture()

LG_Texture * lg_dummy_texture

(

)

To be used if no texture provided

Load the texture only once on first call

Returns

Pointer to dummy texture