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support arbitrary count of billboards per batch (in regards to preallocated short index buffer)

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veclavtalica 2025-01-05 23:36:48 +03:00
parent d7a119a592
commit 4dd028aeae
1 changed files with 82 additions and 76 deletions
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158
src/rendering/twn_billboards.c
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@ -3,6 +3,7 @@
#include "twn_engine_context_c.h"
#include "twn_textures_c.h"
#include "twn_types.h"
#include "twn_util_c.h"
#include "twn_vec.h"
#include <stb_ds.h>
@ -85,88 +86,93 @@ void finally_draw_billboard_batch(struct MeshBatch const *batch,
const Vec2 uv2 = { xr, yr + hr };
const Vec2 uv3 = { xr, yr };
/* emit vertex data */
VertexBuffer const buffer = get_scratch_vertex_array();
VertexBufferBuilder builder = build_vertex_buffer(buffer, sizeof (ElementIndexedBillboard) * primitives_len);
for (size_t batch_n = 0; batch_n <= (primitives_len - 1) / QUAD_ELEMENT_BUFFER_LENGTH; batch_n++) {
for (size_t i = 0; i < primitives_len; ++i) {
struct SpaceBillboard const billboard = ((SpaceBillboard *)(void *)batch->primitives)[i];
/* emit vertex data */
VertexBuffer const buffer = get_scratch_vertex_array();
VertexBufferBuilder builder = build_vertex_buffer(
buffer,
sizeof (ElementIndexedBillboard) * MIN(primitives_len - batch_n * QUAD_ELEMENT_BUFFER_LENGTH, QUAD_ELEMENT_BUFFER_LENGTH));
/* a = (right + up) * size, b = (right - up) * size*/
Vec3 a, b;
if (billboard.cylindrical) {
a = vec3_mul(right_plus_up_cylindrical, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
b = vec3_mul(right_minus_up_cylindrical, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
} else {
a = vec3_mul(right_plus_up, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
b = vec3_mul(right_minus_up, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
for (size_t i = 0; i < primitives_len; ++i) {
struct SpaceBillboard const billboard = ((SpaceBillboard *)(void *)batch->primitives)[batch_n * QUAD_ELEMENT_BUFFER_LENGTH + i];
/* a = (right + up) * size, b = (right - up) * size*/
Vec3 a, b;
if (billboard.cylindrical) {
a = vec3_mul(right_plus_up_cylindrical, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
b = vec3_mul(right_minus_up_cylindrical, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
} else {
a = vec3_mul(right_plus_up, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
b = vec3_mul(right_minus_up, ((Vec3){billboard.size.x, billboard.size.y, billboard.size.x }));
}
struct ElementIndexedBillboard const payload = {
/* TODO: use the flat shading to not set two of the colors */
.c0 = billboard.color,
.c1 = billboard.color,
.c2 = billboard.color,
.c3 = billboard.color,
.uv0 = uv0,
.uv1 = uv1,
.uv2 = uv2,
.uv3 = uv3,
.v0 = vec3_sub(billboard.position, b),
.v1 = vec3_sub(billboard.position, a),
.v2 = vec3_add(billboard.position, b),
.v3 = vec3_add(billboard.position, a),
};
push_to_vertex_buffer_builder(&builder, &payload, sizeof (payload));
}
struct ElementIndexedBillboard const payload = {
/* TODO: use the flat shading to not set two of the colors */
.c0 = billboard.color,
.c1 = billboard.color,
.c2 = billboard.color,
.c3 = billboard.color,
/* commit to drawing */
DeferredCommandDraw command = {0};
.uv0 = uv0,
.uv1 = uv1,
.uv2 = uv2,
.uv3 = uv3,
.v0 = vec3_sub(billboard.position, b),
.v1 = vec3_sub(billboard.position, a),
.v2 = vec3_add(billboard.position, b),
.v3 = vec3_add(billboard.position, a),
command.vertices = (AttributeArrayPointer) {
.arity = 3,
.type = GL_FLOAT,
.stride = offsetof(ElementIndexedBillboard, v1),
.offset = offsetof(ElementIndexedBillboard, v0),
.buffer = buffer
};
push_to_vertex_buffer_builder(&builder, &payload, sizeof (payload));
command.texcoords = (AttributeArrayPointer) {
.arity = 2,
.type = GL_FLOAT,
.stride = offsetof(ElementIndexedBillboard, v1),
.offset = offsetof(ElementIndexedBillboard, uv0),
.buffer = buffer
};
command.colors = (AttributeArrayPointer) {
.arity = 4,
.type = GL_UNSIGNED_BYTE,
.stride = offsetof(ElementIndexedBillboard, v1),
.offset = offsetof(ElementIndexedBillboard, c0),
.buffer = buffer
};
command.textured = true;
command.texture_key = texture_key;
command.element_buffer = get_quad_element_buffer();
command.element_count = 6 * (GLsizei)primitives_len;
command.range_end = 6 * (GLsizei)primitives_len;
/* TODO: support alpha blended case, with distance sort */
TextureMode mode = textures_get_mode(&ctx.texture_cache, texture_key);
if (mode == TEXTURE_MODE_GHOSTLY)
mode = TEXTURE_MODE_SEETHROUGH;
use_texture_mode(mode);
DeferredCommand final_command = {
.type = DEFERRED_COMMAND_TYPE_DRAW,
.draw = command
};
arrpush(deferred_commands, final_command);
}
/* commit to drawing */
DeferredCommandDraw command = {0};
command.vertices = (AttributeArrayPointer) {
.arity = 3,
.type = GL_FLOAT,
.stride = offsetof(ElementIndexedBillboard, v1),
.offset = offsetof(ElementIndexedBillboard, v0),
.buffer = buffer
};
command.texcoords = (AttributeArrayPointer) {
.arity = 2,
.type = GL_FLOAT,
.stride = offsetof(ElementIndexedBillboard, v1),
.offset = offsetof(ElementIndexedBillboard, uv0),
.buffer = buffer
};
command.colors = (AttributeArrayPointer) {
.arity = 4,
.type = GL_UNSIGNED_BYTE,
.stride = offsetof(ElementIndexedBillboard, v1),
.offset = offsetof(ElementIndexedBillboard, c0),
.buffer = buffer
};
command.textured = true;
command.texture_key = texture_key;
command.element_buffer = get_quad_element_buffer();
command.element_count = 6 * (GLsizei)primitives_len;
command.range_end = 6 * (GLsizei)primitives_len;
/* TODO: support alpha blended case, with distance sort */
TextureMode mode = textures_get_mode(&ctx.texture_cache, texture_key);
if (mode == TEXTURE_MODE_GHOSTLY)
mode = TEXTURE_MODE_SEETHROUGH;
use_texture_mode(mode);
DeferredCommand final_command = {
.type = DEFERRED_COMMAND_TYPE_DRAW,
.draw = command
};
arrpush(deferred_commands, final_command);
}