Sara/behaviour-tree-test
1
0
Fork 0
Code Issues Pull requests Projects Releases 2 Packages Wiki Activity Actions

Emulate double precision for regular rendering operation.

Browse source 
We calculate the lost precision on the CPU and pass it into the GPU
so that it can calculate an error-corrected version of the vertex position
This commit is contained in:
clayjohn 2022-09-20 14:21:31 -07:00
parent 6f5704d86f
commit 27a3014f50
9 changed files with 207 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

80
servers/rendering/renderer_rd/shaders/forward_mobile/scene_forward_mobile.glsl
View file

@ -123,6 +123,33 @@ invariant gl_Position;
#define scene_data scene_data_block.data
#ifdef USE_DOUBLE_PRECISION
// Helper functions for emulating double precision when adding floats.
vec3 quick_two_sum(vec3 a, vec3 b, out vec3 out_p) {
vec3 s = a + b;
out_p = b - (s - a);
return s;
}
vec3 two_sum(vec3 a, vec3 b, out vec3 out_p) {
vec3 s = a + b;
vec3 v = s - a;
out_p = (a - (s - v)) + (b - v);
return s;
}
vec3 double_add_vec3(vec3 base_a, vec3 prec_a, vec3 base_b, vec3 prec_b, out vec3 out_precision) {
vec3 s, t, se, te;
s = two_sum(base_a, base_b, se);
t = two_sum(prec_a, prec_b, te);
se += t;
s = quick_two_sum(s, se, se);
se += te;
s = quick_two_sum(s, se, out_precision);
return s;
}
#endif
void main() {
vec4 instance_custom = vec4(0.0);
#if defined(COLOR_USED)
@ -132,6 +159,17 @@ void main() {
bool is_multimesh = bool(draw_call.flags & INSTANCE_FLAGS_MULTIMESH);
mat4 model_matrix = draw_call.transform;
mat4 inv_view_matrix = scene_data.inv_view_matrix;
#ifdef USE_DOUBLE_PRECISION
vec3 model_precision = vec3(model_matrix[0][3], model_matrix[1][3], model_matrix[2][3]);
model_matrix[0][3] = 0.0;
model_matrix[1][3] = 0.0;
model_matrix[2][3] = 0.0;
vec3 view_precision = vec3(inv_view_matrix[0][3], inv_view_matrix[1][3], inv_view_matrix[2][3]);
inv_view_matrix[0][3] = 0.0;
inv_view_matrix[1][3] = 0.0;
inv_view_matrix[2][3] = 0.0;
#endif
mat3 model_normal_matrix;
if (bool(draw_call.flags & INSTANCE_FLAGS_NON_UNIFORM_SCALE)) {
@ -140,11 +178,12 @@ void main() {
model_normal_matrix = mat3(model_matrix);
}
mat4 matrix;
mat4 read_model_matrix = model_matrix;
if (is_multimesh) {
//multimesh, instances are for it
mat4 matrix;
#ifdef USE_PARTICLE_TRAILS
uint trail_size = (draw_call.flags >> INSTANCE_FLAGS_PARTICLE_TRAIL_SHIFT) & INSTANCE_FLAGS_PARTICLE_TRAIL_MASK;
uint stride = 3 + 1 + 1; //particles always uses this format
@ -230,7 +269,15 @@ void main() {
#endif
//transpose
matrix = transpose(matrix);
model_matrix = model_matrix * matrix;
#if !defined(USE_DOUBLE_PRECISION) || defined(SKIP_TRANSFORM_USED) || defined(VERTEX_WORLD_COORDS_USED) || defined(MODEL_MATRIX_USED)
// Normally we can bake the multimesh transform into the model matrix, but when using double precision
// we avoid baking it in so we can emulate high precision.
read_model_matrix = model_matrix * matrix;
#if !defined(USE_DOUBLE_PRECISION) || defined(SKIP_TRANSFORM_USED) || defined(VERTEX_WORLD_COORDS_USED)
model_matrix = read_model_matrix;
#endif // !defined(USE_DOUBLE_PRECISION) || defined(SKIP_TRANSFORM_USED) || defined(VERTEX_WORLD_COORDS_USED)
#endif // !defined(USE_DOUBLE_PRECISION) || defined(SKIP_TRANSFORM_USED) || defined(VERTEX_WORLD_COORDS_USED) || defined(MODEL_MATRIX_USED)
model_normal_matrix = model_normal_matrix * mat3(matrix);
}
@ -297,7 +344,22 @@ void main() {
// using local coordinates (default)
#if !defined(SKIP_TRANSFORM_USED) && !defined(VERTEX_WORLD_COORDS_USED)
#ifdef USE_DOUBLE_PRECISION
// We separate the basis from the origin becasue the basis is fine with single point precision.
// Then we combine the translations from the model matrix and the view matrix using emulated doubles.
// We add the result to the vertex and ignore the final lost precision.
vec3 model_origin = model_matrix[3].xyz;
if (is_multimesh) {
vertex = mat3(matrix) * vertex;
model_origin = double_add_vec3(model_origin, model_precision, matrix[3].xyz, vec3(0.0), model_precision);
}
vertex = mat3(model_matrix) * vertex;
vec3 temp_precision;
vertex += double_add_vec3(model_origin, model_precision, scene_data.inv_view_matrix[3].xyz, view_precision, temp_precision);
vertex = mat3(scene_data.view_matrix) * vertex;
#else
vertex = (modelview * vec4(vertex, 1.0)).xyz;
#endif
#ifdef NORMAL_USED
normal = modelview_normal * normal;
#endif
@ -468,7 +530,6 @@ layout(location = 9) highp in float dp_clip;
//defines to keep compatibility with vertex
#define model_matrix draw_call.transform
#ifdef USE_MULTIVIEW
#define projection_matrix scene_data.projection_matrix_view[ViewIndex]
#define inv_projection_matrix scene_data.inv_projection_matrix_view[ViewIndex]
@ -685,6 +746,17 @@ void main() {
vec2 alpha_texture_coordinate = vec2(0.0, 0.0);
#endif // ALPHA_ANTIALIASING_EDGE_USED
mat4 inv_view_matrix = scene_data.inv_view_matrix;
mat4 read_model_matrix = draw_call.transform;
#ifdef USE_DOUBLE_PRECISION
read_model_matrix[0][3] = 0.0;
read_model_matrix[1][3] = 0.0;
read_model_matrix[2][3] = 0.0;
inv_view_matrix[0][3] = 0.0;
inv_view_matrix[1][3] = 0.0;
inv_view_matrix[2][3] = 0.0;
#endif
{
#CODE : FRAGMENT
}