Techneck/code/source-c/cube_premeshing.c

#include "blocks.h"
#include "state.h"

float tc_cube_front_uv[12] =
{
    0.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 0.0f,
    
    1.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 1.0f
};

float tc_cube_front_xyz[18] =
{
    -0.5f, -0.5f, -0.5f,
    -0.5f,  0.5f, -0.5f,
     0.5f, -0.5f, -0.5f,
    
     0.5f,  0.5f, -0.5f,
     0.5f, -0.5f, -0.5f,
    -0.5f,  0.5f, -0.5f
};



float tc_cube_back_uv[12] =
{
    1.0f, 0.0f,
    0.0f, 1.0f,
    0.0f, 0.0f,
    
    0.0f, 1.0f,
    1.0f, 0.0f,
    1.0f, 1.0f
};

float tc_cube_back_xyz[18] =
{
     0.5f, -0.5f,  0.5f,
    -0.5f,  0.5f,  0.5f,
    -0.5f, -0.5f,  0.5f,
    
    -0.5f,  0.5f,  0.5f,
     0.5f, -0.5f,  0.5f,
     0.5f,  0.5f,  0.5f
};



float tc_cube_west_uv[12] =
{
    0.0f, 1.0f,
    0.0f, 0.0f,
    1.0f, 0.0f,
    
    1.0f, 0.0f,
    1.0f, 1.0f,
    0.0f, 1.0f
};

float tc_cube_west_xyz[18] =
{
    -0.5f,  0.5f, -0.5f,
    -0.5f, -0.5f, -0.5f,
    -0.5f, -0.5f,  0.5f,
    
    -0.5f, -0.5f,  0.5f,
    -0.5f,  0.5f,  0.5f,
    -0.5f,  0.5f, -0.5f
};



float tc_cube_east_uv[12] =
{
    1.0f, 0.0f,
    0.0f, 0.0f,
    0.0f, 1.0f,
    
    0.0f, 1.0f,
    1.0f, 1.0f,
    1.0f, 0.0f
};

float tc_cube_east_xyz[18] =
{
     0.5f, -0.5f,  0.5f,
     0.5f, -0.5f, -0.5f,
     0.5f,  0.5f, -0.5f,
    
     0.5f,  0.5f, -0.5f,
     0.5f,  0.5f,  0.5f,
     0.5f, -0.5f,  0.5f
};



float tc_cube_top_uv[12] =
{
    0.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 0.0f,
    
    0.0f, 1.0f,
    1.0f, 1.0f,
    1.0f, 0.0f
};

float tc_cube_top_xyz[18] =
{
    -0.5f,  0.5f, -0.5f,
    -0.5f,  0.5f,  0.5f,
     0.5f,  0.5f, -0.5f,
    
    -0.5f,  0.5f,  0.5f,
     0.5f,  0.5f,  0.5f,
     0.5f,  0.5f, -0.5f
};



float tc_cube_bottom_uv[12] =
{
    0.0f, 1.0f,
    0.0f, 0.0f,
    1.0f, 0.0f,
    
    1.0f, 1.0f,
    0.0f, 1.0f,
    1.0f, 0.0f
};

float tc_cube_bottom_xyz[18] =
{
    -0.5f, -0.5f,  0.5f,
    -0.5f, -0.5f, -0.5f,
     0.5f, -0.5f, -0.5f,
    
     0.5f, -0.5f,  0.5f,
    -0.5f, -0.5f,  0.5f,
     0.5f, -0.5f, -0.5f
};



void tc_adjust_cube_uvs_for_image(tc_image_s *image, float *face_uvs)
{
    float           uv_per_pixel_w  = 1.0f / image->width;
    float           uv_per_pixel_h  = 1.0f / image->height;
    
    if(image->superimage != NULL)
    {
        uv_per_pixel_w      = 1.0f / image->superimage->width;
        uv_per_pixel_h      = 1.0f / image->superimage->height;
    }
    float           lower_x         = uv_per_pixel_w * ((float) image->x);
    float           lower_y         = uv_per_pixel_h * ((float) image->y);
    float           higher_x        = 1.0f;
    float           higher_y        = 1.0f;
    
    higher_x            = lower_x + uv_per_pixel_w * 8; // image->width;
    higher_y            = lower_y + uv_per_pixel_h * 8; // image->height;
    
    uint32_t        num_floats      = 2 * 6;
    uint32_t        index           = 0;
    
    while(index < num_floats)
    {
        if(face_uvs[index] == 1.0f)
        {
            face_uvs[index] = higher_x;
        }
        else
        {
            face_uvs[index] = lower_x;
        }
        
        ++index;
        
        if(face_uvs[index] == 1.0f)
        {
            face_uvs[index] = higher_y;
        }
        else
        {
            face_uvs[index] = lower_y;
        }
        ++index;
    }
}

tc_cube_side_mesh_s * tc_premesh_cube_block_side(
    tc_image_s *image, float *xyz, float *uv, uint32_t num_vertices
) {
    tc_cube_side_mesh_s        *side            = malloc(sizeof(tc_cube_side_mesh_s));
    side->num_vertices              = num_vertices;
    side->allocation                = malloc(sizeof(float) * num_vertices * (2+3));
    
    side->xyz                       = side->allocation;
    memcpy(side->xyz, xyz, sizeof(float) * num_vertices * 3);
    side->uv                        = &side->allocation[num_vertices*3];
    memcpy(side->uv, uv, sizeof(float) * num_vertices * 2);
    
    tc_adjust_cube_uvs_for_image(image, side->uv);
    
    return side;
}

void tc_premesh_cube(tc_block_entry_s *entry)
{
    tc_image_s                 *front_texture       = tc_block_resolve_name_to_attribute(entry, "front_texture")->value.pointer;
    tc_image_s                 *back_texture        = tc_block_resolve_name_to_attribute(entry, "back_texture")->value.pointer;
    tc_image_s                 *west_texture        = tc_block_resolve_name_to_attribute(entry, "west_texture")->value.pointer;
    tc_image_s                 *east_texture        = tc_block_resolve_name_to_attribute(entry, "east_texture")->value.pointer;
    tc_image_s                 *top_texture         = tc_block_resolve_name_to_attribute(entry, "top_texture")->value.pointer;
    tc_image_s                 *bottom_texture      = tc_block_resolve_name_to_attribute(entry, "bottom_texture")->value.pointer;
    
    tc_cube_side_mesh_s        *front               = tc_premesh_cube_block_side(front_texture,   tc_cube_front_xyz,  tc_cube_front_uv,   6);
    tc_cube_side_mesh_s        *back                = tc_premesh_cube_block_side(back_texture,    tc_cube_back_xyz,   tc_cube_back_uv,    6);
    tc_cube_side_mesh_s        *west                = tc_premesh_cube_block_side(west_texture,    tc_cube_west_xyz,   tc_cube_west_uv,    6);
    tc_cube_side_mesh_s        *east                = tc_premesh_cube_block_side(east_texture,    tc_cube_east_xyz,   tc_cube_east_uv,    6);
    tc_cube_side_mesh_s        *top                 = tc_premesh_cube_block_side(top_texture,     tc_cube_top_xyz,    tc_cube_top_uv,     6);
    tc_cube_side_mesh_s        *bottom              = tc_premesh_cube_block_side(bottom_texture,  tc_cube_bottom_xyz, tc_cube_bottom_uv,  6);
    
    tc_block_attribute_s        front_attribute;
    front_attribute.name            = "south_mesh";
    front_attribute.value.pointer   = front;
    
    tc_block_attribute_s        back_attribute;
    back_attribute.name             = "north_mesh";
    back_attribute.value.pointer    = back;
    
    tc_block_attribute_s        west_attribute;
    west_attribute.name             = "west_mesh";
    west_attribute.value.pointer    = west;
    
    tc_block_attribute_s        east_attribute;
    east_attribute.name             = "east_mesh";
    east_attribute.value.pointer    = east;
    
    tc_block_attribute_s        top_attribute;
    top_attribute.name              = "top_mesh";
    top_attribute.value.pointer     = top;
    
    tc_block_attribute_s        bottom_attribute;
    bottom_attribute.name           = "bottom_mesh";
    bottom_attribute.value.pointer  = bottom;
    
    tc_add_attribute_to_block_entry(entry, front_attribute);
    tc_add_attribute_to_block_entry(entry, back_attribute);
    tc_add_attribute_to_block_entry(entry, east_attribute);
    tc_add_attribute_to_block_entry(entry, west_attribute);
    tc_add_attribute_to_block_entry(entry, top_attribute);
    tc_add_attribute_to_block_entry(entry, bottom_attribute);
}