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Initial texturing support
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@Daft-Freak
Daft-Freak committed Nov 4, 2023
1 parent 7403f86 commit 8d73385
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Showing 3 changed files with 146 additions and 5 deletions.
2 changes: 2 additions & 0 deletions model.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,8 @@ void model_lit_shader(const uint8_t *in, Render3D::VertexOutData *out, const Ren
out->r = int32_t(dot * vertex->r);
out->g = int32_t(dot * vertex->g);
out->b = int32_t(dot * vertex->b);

out->tex_index = 0;
}

Model::Model(const uint8_t *asset_data)
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139 changes: 135 additions & 4 deletions render-3d.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,10 @@ void fixed32_mvp_pos_shader(const uint8_t *in, Render3D::VertexOutData *out, con
}

Render3D::Render3D() : tile_surf(reinterpret_cast<uint8_t *>(tile_colour_buffer), PixelFormat::BGR555, {tile_width, tile_height})
{}
{
for(int i = 0; i < max_textures; i++)
textures[i] = nullptr;
}

void Render3D::draw(int count, const uint8_t *ptr)
{
Expand Down Expand Up @@ -159,6 +162,11 @@ void Render3D::set_vertex_shader(VertexShaderFunc shader)
vertex_shader = shader;
}

void Render3D::set_texture(blit::Surface *tex, int index)
{
textures[index] = tex;
}

int Render3D::get_transformed_vertex_count() const
{
if(!transformed_vertex_ptr)
Expand Down Expand Up @@ -338,21 +346,42 @@ void blit_fast_code(Render3D::fill_triangle)(VertexOutData *data, blit::Point ti
{data[2].r, data[2].g, data[2].b}
};

// tex coords/enable
auto tex = data[0].tex_index ? textures[data[0].tex_index - 1] : nullptr;

Fixed16<12> u[3]{data[0].u, data[1].u, data[2].u};
Fixed16<12> v[3]{data[0].v, data[1].v, data[2].v};

// sort points
if(p0.y > p2.y)
{
std::swap(p0, p2);
std::swap(cols[0], cols[2]);
if(tex)
{
std::swap(u[0], u[2]);
std::swap(v[0], v[2]);
}
}
if(p0.y > p1.y)
{
std::swap(p0, p1);
std::swap(cols[0], cols[1]);
if(tex)
{
std::swap(u[0], u[1]);
std::swap(v[0], v[1]);
}
}
if(p1.y > p2.y)
{
std::swap(p1, p2);
std::swap(cols[1], cols[2]);
if(tex)
{
std::swap(u[1], u[2]);
std::swap(v[1], v[2]);
}
}

auto p1M0 = p1 - p0;
Expand Down Expand Up @@ -416,7 +445,16 @@ void blit_fast_code(Render3D::fill_triangle)(VertexOutData *data, blit::Point ti
auto start_col = cols[0] + col2M0 * y_frac1;
auto end_col = cols[0] + col1M0 * y_frac2;

gradient_h_line(int32_t(start_x), int32_t(end_x), start_z, end_z, y, start_col, end_col);
if(tex)
{
auto start_u = u[0] + (u[2] - u[0]) * y_frac1;
auto start_v = v[0] + (v[2] - v[0]) * y_frac1;
auto end_u = u[0] + (u[1] - u[0]) * y_frac2;
auto end_v = v[0] + (v[1] - v[0]) * y_frac2;
textured_h_line(int32_t(start_x), int32_t(end_x), start_z, end_z, y, start_col, end_col, tex, start_u, end_u, start_v, end_v);
}
else
gradient_h_line(int32_t(start_x), int32_t(end_x), start_z, end_z, y, start_col, end_col);
}

#ifdef PICO_INTERP
Expand Down Expand Up @@ -478,8 +516,16 @@ void blit_fast_code(Render3D::fill_triangle)(VertexOutData *data, blit::Point ti

auto start_col = cols[0] + col2M0 * y_frac1;
auto end_col = cols[1] + col2M1 * y_frac2;

gradient_h_line(int32_t(start_x), int32_t(end_x), start_z, end_z, y, start_col, end_col);
if(tex)
{
auto start_u = u[0] + (u[2] - u[0]) * y_frac1;
auto start_v = v[0] + (v[2] - v[0]) * y_frac1;
auto end_u = u[1] + (u[2] - u[1]) * y_frac2;
auto end_v = v[1] + (v[2] - v[1]) * y_frac2;
textured_h_line(int32_t(start_x), int32_t(end_x), start_z, end_z, y, start_col, end_col, tex, start_u, end_u, start_v, end_v);
}
else
gradient_h_line(int32_t(start_x), int32_t(end_x), start_z, end_z, y, start_col, end_col);
}
}
}
Expand Down Expand Up @@ -551,6 +597,91 @@ void blit_fast_code(Render3D::gradient_h_line)(int x1, int x2, uint16_t z1, uint
}
}

// the above, but with texture mapping
void blit_fast_code(Render3D::textured_h_line)(int x1, int x2, uint16_t z1, uint16_t z2, int y, Pen col1, Pen col2, Surface *tex, Fixed16<12> u1, Fixed16<12> u2, Fixed16<12> v1, Fixed16<12> v2)
{
if(x1 > x2)
{
std::swap(x1, x2);
std::swap(z1, z2);
std::swap(col1, col2);
std::swap(u1, u2);
std::swap(v1, v2);
}

// the triangle may be in the tile, but this line is definitely not
if(x1 > tile_width || x2 < 0)
return;

auto x_scale = Fixed32<>(1) / (x2 - x1);

// depth
int z_diff = z2 - z1;
auto z_step = Fixed32<15>(x_scale) * z_diff;
auto z = Fixed32<15>(z1);

// colour
auto col_diff = col2 - col1;

auto r_step = x_scale * col_diff.r;
auto g_step = x_scale * col_diff.g;
auto b_step = x_scale * col_diff.b;

auto r = Fixed32<>(col1.r);
auto g = Fixed32<>(col1.g);
auto b = Fixed32<>(col1.b);

// tex
auto u_step = Fixed32<>(u2 - u1) * x_scale;
auto v_step = Fixed32<>(v2 - v1) * x_scale;
auto u = Fixed32<>(u1);
auto v = Fixed32<>(v1);

// clamp x
if(x2 > tile_width)
x2 = tile_width;

if(x1 < 0)
{
z += z_step * -x1;
r += r_step * -x1;
g += g_step * -x1;
b += b_step * -x1;
u += u_step * -x1;
v += v_step * -x1;
x1 = 0;
}

auto col_ptr = tile_colour_buffer + x1 + y * tile_width;
auto depth_ptr = tile_depth_buffer + x1 + y * tile_width;

#ifdef PICO_MULTICORE
auto core_num = get_core_num();
col_ptr += core_num * tile_width * tile_height;
depth_ptr += core_num * tile_width * tile_height;
#endif

auto end_ptr = col_ptr + (x2 - x1);

// TODO: config?
constexpr int tex_size_bits = 8;
constexpr int tex_size = 1 << tex_size_bits;

for(; col_ptr < end_ptr; col_ptr++, depth_ptr++, z += z_step, r += r_step, g += g_step, b += b_step, u += u_step, v += v_step)
{
if(int32_t(z) > *depth_ptr)
continue;

// this could be optimised
auto tex_col = tex->get_pixel({(u.raw() >> (16 - tex_size_bits)) & (tex_size - 1), (v.raw() >> (16 - tex_size_bits)) & (tex_size - 1)});

Pen col{(uint8_t(r) * tex_col.r) >> 8, (uint8_t(g) * tex_col.g) >> 8, (uint8_t(b) * tex_col.b) >> 8};

*col_ptr = pack_colour(col);
*depth_ptr = int32_t(z);
}
}

uint16_t Render3D::pack_colour(Pen p)
{
#ifdef BLIT_BOARD_PIMORONI_PICOVISION
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10 changes: 9 additions & 1 deletion render-3d.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,8 @@ class Render3D
struct VertexOutData
{
Fixed32<> x, y, z, w;
uint8_t r, g, b, a;
uint8_t r, g, b, tex_index;
Fixed16<12> u, v;
};

using VertexShaderFunc = void(*)(const uint8_t *, VertexOutData *, const Render3D &);
Expand All @@ -40,6 +41,9 @@ class Render3D
void set_position_shader(VertexShaderFunc shader);
void set_vertex_shader(VertexShaderFunc shader);

// tex would be const but blit::Surface is missing some consts...
void set_texture(blit::Surface *tex, int index = 0);

int get_transformed_vertex_count() const;

void rasterise();
Expand All @@ -50,6 +54,7 @@ class Render3D
void fill_triangle(VertexOutData *data, blit::Point tile_pos);

void gradient_h_line(int x1, int x2, uint16_t z1, uint16_t z2, int y, blit::Pen col1, blit::Pen col2);
void textured_h_line(int x1, int x2, uint16_t z1, uint16_t z2, int y, blit::Pen col1, blit::Pen col2, blit::Surface *tex, Fixed16<12> u1, Fixed16<12> u2, Fixed16<12> v1, Fixed16<12> v2);

uint16_t pack_colour(blit::Pen p);
blit::Pen unpack_colour(uint16_t c);
Expand All @@ -60,6 +65,9 @@ class Render3D
int vertex_stride = 3;
VertexShaderFunc position_shader = nullptr, vertex_shader = nullptr;

static constexpr int max_textures = 1;
blit::Surface *textures[max_textures];

VertexOutData transformed_vertices[1024];
VertexOutData *transformed_vertex_ptr = nullptr;

Expand Down

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