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package resource
import "core:log"
import "core:math"
import bk "../backend"
MAX_MESHES :: 256
// Legacy 48-byte vertex (position + normal + tex_coord + color).
// Kept for backward compatibility with gen_mesh_custom.
Mesh_Vertex :: struct {
position: [3]f32,
normal: [3]f32,
tex_coord: [2]f32,
color: [4]f32,
}
// 32-byte vertex (position + normal + tex_coord). Used by procedural generators.
Mesh_Vertex_PNU :: struct {
position: [3]f32,
normal: [3]f32,
tex_coord: [2]f32,
}
Internal_Mesh :: struct {
vertex_buffer: bk.Buffer_Handle,
index_buffer: bk.Buffer_Handle,
vertex_count: i32,
index_count: i32,
layout: bk.Vertex_Layout,
active: bool,
}
allocate_mesh_slot :: proc(state: ^Resource_State) -> (u32, bool) {
for i in 1..<u32(MAX_MESHES) {
if !state.meshes[i].active {
return i, true
}
}
log.error("gpu/resource: mesh pool exhausted")
return 0, false
}
// Upload raw vertex data with an explicit layout descriptor.
upload_mesh_raw :: proc(
state: ^Resource_State,
b: ^bk.Backend,
vertex_data: rawptr,
vertex_data_size: int,
vertex_count: i32,
indices: []u32,
layout: bk.Vertex_Layout,
) -> (id: u32, index_count: i32, ok: bool) {
slot, slot_ok := allocate_mesh_slot(state)
if !slot_ok {
return 0, 0, false
}
ib_size := len(indices) * size_of(u32)
vb, vb_ok := b.create_buffer_staged(
vertex_data, vertex_data_size,
{.Vertex},
)
if !vb_ok {
log.error("gpu/resource: failed to create mesh vertex buffer")
return 0, 0, false
}
ib, ib_ok := b.create_buffer_staged(
raw_data(indices), ib_size,
{.Index},
)
if !ib_ok {
b.destroy_buffer(vb)
log.error("gpu/resource: failed to create mesh index buffer")
return 0, 0, false
}
state.meshes[slot] = Internal_Mesh{
vertex_buffer = vb,
index_buffer = ib,
vertex_count = vertex_count,
index_count = i32(len(indices)),
layout = layout,
active = true,
}
return slot, i32(len(indices)), true
}
// Upload a []Mesh_Vertex slice (legacy 48-byte format).
upload_mesh :: proc(
state: ^Resource_State,
b: ^bk.Backend,
vertices: []Mesh_Vertex,
indices: []u32,
) -> (id: u32, vertex_count, index_count: i32, ok: bool) {
mid, ic, upload_ok := upload_mesh_raw(
state, b,
raw_data(vertices), len(vertices) * size_of(Mesh_Vertex),
i32(len(vertices)), indices,
bk.LAYOUT_POS_NORM_UV_COLOR,
)
if !upload_ok {
return 0, 0, 0, false
}
return mid, i32(len(vertices)), ic, true
}
get_mesh_layout :: proc(state: ^Resource_State, id: u32) -> (bk.Vertex_Layout, bool) {
if id >= MAX_MESHES || !state.meshes[id].active {
return {}, false
}
return state.meshes[id].layout, true
}
get_mesh_info :: proc(state: ^Resource_State, id: u32) -> (vertex_count, index_count: i32, layout: bk.Vertex_Layout, ok: bool) {
if id >= MAX_MESHES || !state.meshes[id].active {
return 0, 0, {}, false
}
m := &state.meshes[id]
return m.vertex_count, m.index_count, m.layout, true
}
unload_mesh :: proc(state: ^Resource_State, b: ^bk.Backend, id: u32) {
if id == 0 || id >= MAX_MESHES || !state.meshes[id].active {
return
}
b.destroy_buffer(state.meshes[id].vertex_buffer)
b.destroy_buffer(state.meshes[id].index_buffer)
state.meshes[id].active = false
}
get_mesh_buffers :: proc(state: ^Resource_State, id: u32) -> (vb: bk.Buffer_Handle, ib: bk.Buffer_Handle, index_count: i32, ok: bool) {
if id >= MAX_MESHES || !state.meshes[id].active {
return {}, {}, 0, false
}
m := &state.meshes[id]
return m.vertex_buffer, m.index_buffer, m.index_count, true
}
shutdown_meshes :: proc(state: ^Resource_State, b: ^bk.Backend) {
for i in 0..<u32(MAX_MESHES) {
if state.meshes[i].active {
b.destroy_buffer(state.meshes[i].vertex_buffer)
b.destroy_buffer(state.meshes[i].index_buffer)
state.meshes[i].active = false
}
}
}
// --- Procedural Geometry Generators ---
// Produce LAYOUT_POS_NORM_UV (32 bytes) — no vertex color.
// 3D shaders get color from material push constants.
gen_cube_geometry :: proc(w, h, l: f32) -> ([]Mesh_Vertex_PNU, []u32) {
hw := w * 0.5
hh := h * 0.5
hl := l * 0.5
vertices := make([]Mesh_Vertex_PNU, 24)
indices := make([]u32, 36)
// Front face (+Z)
vertices[0] = {{-hw, -hh, hl}, { 0, 0, 1}, {0, 1}}
vertices[1] = {{ hw, -hh, hl}, { 0, 0, 1}, {1, 1}}
vertices[2] = {{ hw, hh, hl}, { 0, 0, 1}, {1, 0}}
vertices[3] = {{-hw, hh, hl}, { 0, 0, 1}, {0, 0}}
// Back face (-Z)
vertices[4] = {{ hw, -hh, -hl}, { 0, 0, -1}, {0, 1}}
vertices[5] = {{-hw, -hh, -hl}, { 0, 0, -1}, {1, 1}}
vertices[6] = {{-hw, hh, -hl}, { 0, 0, -1}, {1, 0}}
vertices[7] = {{ hw, hh, -hl}, { 0, 0, -1}, {0, 0}}
// Top face (+Y)
vertices[8] = {{-hw, hh, hl}, { 0, 1, 0}, {0, 1}}
vertices[9] = {{ hw, hh, hl}, { 0, 1, 0}, {1, 1}}
vertices[10] = {{ hw, hh, -hl}, { 0, 1, 0}, {1, 0}}
vertices[11] = {{-hw, hh, -hl}, { 0, 1, 0}, {0, 0}}
// Bottom face (-Y)
vertices[12] = {{-hw, -hh, -hl}, { 0, -1, 0}, {0, 1}}
vertices[13] = {{ hw, -hh, -hl}, { 0, -1, 0}, {1, 1}}
vertices[14] = {{ hw, -hh, hl}, { 0, -1, 0}, {1, 0}}
vertices[15] = {{-hw, -hh, hl}, { 0, -1, 0}, {0, 0}}
// Right face (+X)
vertices[16] = {{ hw, -hh, hl}, { 1, 0, 0}, {0, 1}}
vertices[17] = {{ hw, -hh, -hl}, { 1, 0, 0}, {1, 1}}
vertices[18] = {{ hw, hh, -hl}, { 1, 0, 0}, {1, 0}}
vertices[19] = {{ hw, hh, hl}, { 1, 0, 0}, {0, 0}}
// Left face (-X)
vertices[20] = {{-hw, -hh, -hl}, {-1, 0, 0}, {0, 1}}
vertices[21] = {{-hw, -hh, hl}, {-1, 0, 0}, {1, 1}}
vertices[22] = {{-hw, hh, hl}, {-1, 0, 0}, {1, 0}}
vertices[23] = {{-hw, hh, -hl}, {-1, 0, 0}, {0, 0}}
// Indices (two triangles per face, CCW winding)
for face in 0..<u32(6) {
base := face * 4
idx := face * 6
indices[idx + 0] = base + 0
indices[idx + 1] = base + 1
indices[idx + 2] = base + 2
indices[idx + 3] = base + 0
indices[idx + 4] = base + 2
indices[idx + 5] = base + 3
}
return vertices, indices
}
gen_sphere_geometry :: proc(radius: f32, rings, slices: i32) -> ([]Mesh_Vertex_PNU, []u32) {
vert_count := int((rings + 1) * (slices + 1))
idx_count := int(rings * slices * 6)
vertices := make([]Mesh_Vertex_PNU, vert_count)
indices := make([]u32, idx_count)
vi := 0
ii := 0
for ring in 0..=rings {
phi := f32(ring) * math.PI / f32(rings)
sp := math.sin(phi)
cp := math.cos(phi)
for slice in 0..=slices {
theta := f32(slice) * 2.0 * math.PI / f32(slices)
st := math.sin(theta)
ct := math.cos(theta)
nx := ct * sp
ny := cp
nz := st * sp
vertices[vi] = {
position = {nx * radius, ny * radius, nz * radius},
normal = {nx, ny, nz},
tex_coord = {f32(slice) / f32(slices), f32(ring) / f32(rings)},
}
vi += 1
}
}
for ring in 0..<rings {
for slice in 0..<slices {
a := u32(ring * (slices + 1) + slice)
b := a + u32(slices) + 1
indices[ii + 0] = a
indices[ii + 1] = a + 1
indices[ii + 2] = b
indices[ii + 3] = a + 1
indices[ii + 4] = b + 1
indices[ii + 5] = b
ii += 6
}
}
return vertices, indices
}
gen_plane_geometry :: proc(w, l: f32, res_x, res_z: i32) -> ([]Mesh_Vertex_PNU, []u32) {
vert_count := int((res_x + 1) * (res_z + 1))
idx_count := int(res_x * res_z * 6)
vertices := make([]Mesh_Vertex_PNU, vert_count)
indices := make([]u32, idx_count)
vi := 0
ii := 0
for z in 0..=res_z {
for x in 0..=res_x {
fx := f32(x) / f32(res_x)
fz := f32(z) / f32(res_z)
vertices[vi] = {
position = {(fx - 0.5) * w, 0, (fz - 0.5) * l},
normal = {0, 1, 0},
tex_coord = {fx, fz},
}
vi += 1
}
}
for z in 0..<res_z {
for x in 0..<res_x {
a := u32(z * (res_x + 1) + x)
b := a + u32(res_x) + 1
indices[ii + 0] = a
indices[ii + 1] = b
indices[ii + 2] = a + 1
indices[ii + 3] = a + 1
indices[ii + 4] = b
indices[ii + 5] = b + 1
ii += 6
}
}
return vertices, indices
}
gen_grid_geometry :: proc(slices: i32, spacing, thickness: f32) -> ([]Mesh_Vertex_PNU, []u32) {
line_count := max(slices + 1, 0) * 2
vertices := make([]Mesh_Vertex_PNU, int(line_count * 4))
indices := make([]u32, int(line_count * 12))
half := f32(slices) * spacing * 0.5
half_t := thickness * 0.5
vi := 0
ii := 0
add_quad :: proc(vertices: []Mesh_Vertex_PNU, indices: []u32, vi, ii: ^int, x0, z0, x1, z1: f32) {
base := u32(vi^)
vertices[vi^ + 0] = {{x0, 0, z0}, {0, 1, 0}, {0, 0}}
vertices[vi^ + 1] = {{x1, 0, z0}, {0, 1, 0}, {1, 0}}
vertices[vi^ + 2] = {{x1, 0, z1}, {0, 1, 0}, {1, 1}}
vertices[vi^ + 3] = {{x0, 0, z1}, {0, 1, 0}, {0, 1}}
// Emit both windings so the debug grid remains visible above and below with back-face culling.
indices[ii^ + 0] = base + 0
indices[ii^ + 1] = base + 2
indices[ii^ + 2] = base + 1
indices[ii^ + 3] = base + 0
indices[ii^ + 4] = base + 3
indices[ii^ + 5] = base + 2
indices[ii^ + 6] = base + 0
indices[ii^ + 7] = base + 1
indices[ii^ + 8] = base + 2
indices[ii^ + 9] = base + 0
indices[ii^ + 10] = base + 2
indices[ii^ + 11] = base + 3
vi^ += 4
ii^ += 12
}
for i in 0..=slices {
x := -half + f32(i) * spacing
add_quad(vertices, indices, &vi, &ii, x - half_t, -half, x + half_t, half)
z := -half + f32(i) * spacing
add_quad(vertices, indices, &vi, &ii, -half, z - half_t, half, z + half_t)
}
return vertices, indices
}