gecko-dev/gfx/webrender/res/prim_shared.glsl

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GLSL

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include rect,render_task,gpu_cache,snap,transform
#define EXTEND_MODE_CLAMP 0
#define EXTEND_MODE_REPEAT 1
#define SUBPX_DIR_NONE 0
#define SUBPX_DIR_HORIZONTAL 1
#define SUBPX_DIR_VERTICAL 2
#define SUBPX_DIR_MIXED 3
#define RASTER_LOCAL 0
#define RASTER_SCREEN 1
uniform sampler2DArray sPrevPassAlpha;
uniform sampler2DArray sPrevPassColor;
vec2 clamp_rect(vec2 pt, RectWithSize rect) {
return clamp(pt, rect.p0, rect.p0 + rect.size);
}
// TODO: convert back to RectWithEndPoint if driver issues are resolved, if ever.
flat varying vec4 vClipMaskUvBounds;
// XY and W are homogeneous coordinates, Z is the layer index
varying vec4 vClipMaskUv;
#ifdef WR_VERTEX_SHADER
#define COLOR_MODE_FROM_PASS 0
#define COLOR_MODE_ALPHA 1
#define COLOR_MODE_SUBPX_CONST_COLOR 2
#define COLOR_MODE_SUBPX_BG_PASS0 3
#define COLOR_MODE_SUBPX_BG_PASS1 4
#define COLOR_MODE_SUBPX_BG_PASS2 5
#define COLOR_MODE_SUBPX_DUAL_SOURCE 6
#define COLOR_MODE_BITMAP 7
#define COLOR_MODE_COLOR_BITMAP 8
#define COLOR_MODE_IMAGE 9
uniform HIGHP_SAMPLER_FLOAT sampler2D sPrimitiveHeadersF;
uniform HIGHP_SAMPLER_FLOAT isampler2D sPrimitiveHeadersI;
// Instanced attributes
in ivec4 aData;
#define VECS_PER_PRIM_HEADER_F 2U
#define VECS_PER_PRIM_HEADER_I 2U
struct PrimitiveHeader {
RectWithSize local_rect;
RectWithSize local_clip_rect;
float z;
int specific_prim_address;
int render_task_index;
int clip_task_index;
int transform_id;
ivec3 user_data;
};
PrimitiveHeader fetch_prim_header(int index) {
PrimitiveHeader ph;
ivec2 uv_f = get_fetch_uv(index, VECS_PER_PRIM_HEADER_F);
vec4 local_rect = TEXEL_FETCH(sPrimitiveHeadersF, uv_f, 0, ivec2(0, 0));
vec4 local_clip_rect = TEXEL_FETCH(sPrimitiveHeadersF, uv_f, 0, ivec2(1, 0));
ph.local_rect = RectWithSize(local_rect.xy, local_rect.zw);
ph.local_clip_rect = RectWithSize(local_clip_rect.xy, local_clip_rect.zw);
ivec2 uv_i = get_fetch_uv(index, VECS_PER_PRIM_HEADER_I);
ivec4 data0 = TEXEL_FETCH(sPrimitiveHeadersI, uv_i, 0, ivec2(0, 0));
ivec4 data1 = TEXEL_FETCH(sPrimitiveHeadersI, uv_i, 0, ivec2(1, 0));
ph.z = float(data0.x);
ph.render_task_index = data0.y;
ph.specific_prim_address = data0.z;
ph.clip_task_index = data0.w;
ph.transform_id = data1.x;
ph.user_data = data1.yzw;
return ph;
}
struct VertexInfo {
vec2 local_pos;
vec2 snap_offset;
vec4 world_pos;
};
VertexInfo write_vertex(RectWithSize instance_rect,
RectWithSize local_clip_rect,
float z,
Transform transform,
PictureTask task,
RectWithSize snap_rect) {
// Select the corner of the local rect that we are processing.
vec2 local_pos = instance_rect.p0 + instance_rect.size * aPosition.xy;
// Clamp to the two local clip rects.
vec2 clamped_local_pos = clamp_rect(local_pos, local_clip_rect);
/// Compute the snapping offset.
vec2 snap_offset = compute_snap_offset(
clamped_local_pos,
transform.m,
snap_rect,
task.common_data.device_pixel_scale
);
// Transform the current vertex to world space.
vec4 world_pos = transform.m * vec4(clamped_local_pos, 0.0, 1.0);
// Convert the world positions to device pixel space.
vec2 device_pos = world_pos.xy * task.common_data.device_pixel_scale;
// Apply offsets for the render task to get correct screen location.
vec2 final_offset = snap_offset - task.content_origin + task.common_data.task_rect.p0;
gl_Position = uTransform * vec4(device_pos + final_offset * world_pos.w, z * world_pos.w, world_pos.w);
VertexInfo vi = VertexInfo(
clamped_local_pos,
snap_offset,
world_pos
);
return vi;
}
float cross2(vec2 v0, vec2 v1) {
return v0.x * v1.y - v0.y * v1.x;
}
// Return intersection of line (p0,p1) and line (p2,p3)
vec2 intersect_lines(vec2 p0, vec2 p1, vec2 p2, vec2 p3) {
vec2 d0 = p0 - p1;
vec2 d1 = p2 - p3;
float s0 = cross2(p0, p1);
float s1 = cross2(p2, p3);
float d = cross2(d0, d1);
float nx = s0 * d1.x - d0.x * s1;
float ny = s0 * d1.y - d0.y * s1;
return vec2(nx / d, ny / d);
}
VertexInfo write_transform_vertex(RectWithSize local_segment_rect,
RectWithSize local_prim_rect,
RectWithSize local_clip_rect,
vec4 clip_edge_mask,
float z,
Transform transform,
PictureTask task) {
// Calculate a clip rect from local_rect + local clip
RectWithEndpoint clip_rect = to_rect_with_endpoint(local_clip_rect);
RectWithEndpoint segment_rect = to_rect_with_endpoint(local_segment_rect);
segment_rect.p0 = clamp(segment_rect.p0, clip_rect.p0, clip_rect.p1);
segment_rect.p1 = clamp(segment_rect.p1, clip_rect.p0, clip_rect.p1);
// Calculate a clip rect from local_rect + local clip
RectWithEndpoint prim_rect = to_rect_with_endpoint(local_prim_rect);
prim_rect.p0 = clamp(prim_rect.p0, clip_rect.p0, clip_rect.p1);
prim_rect.p1 = clamp(prim_rect.p1, clip_rect.p0, clip_rect.p1);
// As this is a transform shader, extrude by 2 (local space) pixels
// in each direction. This gives enough space around the edge to
// apply distance anti-aliasing. Technically, it:
// (a) slightly over-estimates the number of required pixels in the simple case.
// (b) might not provide enough edge in edge case perspective projections.
// However, it's fast and simple. If / when we ever run into issues, we
// can do some math on the projection matrix to work out a variable
// amount to extrude.
// Only extrude along edges where we are going to apply AA.
float extrude_amount = 2.0;
vec4 extrude_distance = vec4(extrude_amount) * clip_edge_mask;
local_segment_rect.p0 -= extrude_distance.xy;
local_segment_rect.size += extrude_distance.xy + extrude_distance.zw;
// Select the corner of the local rect that we are processing.
vec2 local_pos = local_segment_rect.p0 + local_segment_rect.size * aPosition.xy;
// Convert the world positions to device pixel space.
vec2 task_offset = task.common_data.task_rect.p0 - task.content_origin;
// Transform the current vertex to the world cpace.
vec4 world_pos = transform.m * vec4(local_pos, 0.0, 1.0);
vec4 final_pos = vec4(
world_pos.xy * task.common_data.device_pixel_scale + task_offset * world_pos.w,
z * world_pos.w,
world_pos.w
);
gl_Position = uTransform * final_pos;
init_transform_vs(mix(
vec4(prim_rect.p0, prim_rect.p1),
vec4(segment_rect.p0, segment_rect.p1),
clip_edge_mask
));
VertexInfo vi = VertexInfo(
local_pos,
vec2(0.0),
world_pos
);
return vi;
}
void write_clip(vec4 world_pos, vec2 snap_offset, ClipArea area) {
vec2 uv = world_pos.xy * area.common_data.device_pixel_scale +
world_pos.w * (snap_offset + area.common_data.task_rect.p0 - area.screen_origin);
vClipMaskUvBounds = vec4(
area.common_data.task_rect.p0,
area.common_data.task_rect.p0 + area.common_data.task_rect.size
);
vClipMaskUv = vec4(uv, area.common_data.texture_layer_index, world_pos.w);
}
#endif //WR_VERTEX_SHADER
#ifdef WR_FRAGMENT_SHADER
float do_clip() {
// check for the dummy bounds, which are given to the opaque objects
if (vClipMaskUvBounds.xy == vClipMaskUvBounds.zw) {
return 1.0;
}
// anything outside of the mask is considered transparent
//Note: we assume gl_FragCoord.w == interpolated(1 / vClipMaskUv.w)
vec2 mask_uv = vClipMaskUv.xy * gl_FragCoord.w;
bvec2 left = lessThanEqual(vClipMaskUvBounds.xy, mask_uv); // inclusive
bvec2 right = greaterThan(vClipMaskUvBounds.zw, mask_uv); // non-inclusive
// bail out if the pixel is outside the valid bounds
if (!all(bvec4(left, right))) {
return 0.0;
}
// finally, the slow path - fetch the mask value from an image
// Note the Z getting rounded to the nearest integer because the variable
// is still interpolated and becomes a subject of precision-caused
// fluctuations, see https://bugzilla.mozilla.org/show_bug.cgi?id=1491911
ivec3 tc = ivec3(mask_uv, vClipMaskUv.z + 0.5);
return texelFetch(sPrevPassAlpha, tc, 0).r;
}
#ifdef WR_FEATURE_DITHERING
vec4 dither(vec4 color) {
const int matrix_mask = 7;
ivec2 pos = ivec2(gl_FragCoord.xy) & ivec2(matrix_mask);
float noise_normalized = (texelFetch(sDither, pos, 0).r * 255.0 + 0.5) / 64.0;
float noise = (noise_normalized - 0.5) / 256.0; // scale down to the unit length
return color + vec4(noise, noise, noise, 0);
}
#else
vec4 dither(vec4 color) {
return color;
}
#endif //WR_FEATURE_DITHERING
vec4 sample_gradient(int address, float offset, float gradient_repeat) {
// Modulo the offset if the gradient repeats.
float x = mix(offset, fract(offset), gradient_repeat);
// Calculate the color entry index to use for this offset:
// offsets < 0 use the first color entry, 0
// offsets from [0, 1) use the color entries in the range of [1, N-1)
// offsets >= 1 use the last color entry, N-1
// so transform the range [0, 1) -> [1, N-1)
// TODO(gw): In the future we might consider making the size of the
// LUT vary based on number / distribution of stops in the gradient.
const int GRADIENT_ENTRIES = 128;
x = 1.0 + x * float(GRADIENT_ENTRIES);
// Calculate the texel to index into the gradient color entries:
// floor(x) is the gradient color entry index
// fract(x) is the linear filtering factor between start and end
int lut_offset = 2 * int(floor(x)); // There is a [start, end] color per entry.
// Ensure we don't fetch outside the valid range of the LUT.
lut_offset = clamp(lut_offset, 0, 2 * (GRADIENT_ENTRIES + 1));
// Fetch the start and end color.
vec4 texels[2] = fetch_from_gpu_cache_2(address + lut_offset);
// Finally interpolate and apply dithering
return dither(mix(texels[0], texels[1], fract(x)));
}
#endif //WR_FRAGMENT_SHADER