clip_shared.glsl - mozsearch

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/* 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,transform

#ifdef WR_VERTEX_SHADER

PER_INSTANCE in vec4 aClipDeviceArea;

PER_INSTANCE in vec4 aClipOrigins;

PER_INSTANCE in float aDevicePixelScale;

PER_INSTANCE in ivec2 aTransformIds;

struct ClipMaskInstanceCommon {

    RectWithEndpoint sub_rect;

    vec2 task_origin;

    vec2 screen_origin;

    float device_pixel_scale;

    int clip_transform_id;

    int prim_transform_id;

};

ClipMaskInstanceCommon fetch_clip_item_common() {

    ClipMaskInstanceCommon cmi;

    cmi.sub_rect = RectWithEndpoint(aClipDeviceArea.xy, aClipDeviceArea.zw);

    cmi.task_origin = aClipOrigins.xy;

    cmi.screen_origin = aClipOrigins.zw;

    cmi.device_pixel_scale = aDevicePixelScale;

    cmi.clip_transform_id = aTransformIds.x;

    cmi.prim_transform_id = aTransformIds.y;

    return cmi;

struct ClipVertexInfo {

    vec4 local_pos;

    RectWithEndpoint clipped_local_rect;

};

// The transformed vertex function that always covers the whole clip area,

// which is the intersection of all clip instances of a given primitive

ClipVertexInfo write_clip_tile_vertex(RectWithEndpoint local_clip_rect,

                                      Transform prim_transform,

                                      Transform clip_transform,

                                      RectWithEndpoint sub_rect,

                                      vec2 task_origin,

                                      vec2 screen_origin,

                                      float device_pixel_scale) {

    vec2 device_pos = screen_origin + mix(sub_rect.p0, sub_rect.p1, aPosition.xy);

    vec2 world_pos = device_pos / device_pixel_scale;

    vec4 pos = prim_transform.m * vec4(world_pos, 0.0, 1.0);

    pos.xyz /= pos.w;

    vec4 p = get_node_pos(pos.xy, clip_transform);

    vec4 local_pos = p * pos.w;

    //TODO: Interpolate in clip space, where "local_pos.w" contains

    // the W of the homogeneous transform *from* clip space into the world.

    //    float interpolate_w = 1.0 / local_pos.w;

    // This is problematic today, because the W<=0 hemisphere is going to be

    // clipped, while we currently want this shader to fill out the whole rect.

    // We can therefore simplify this when the clip construction is rewritten

    // to only affect the areas touched by a clip.

    vec4 vertex_pos = vec4(

        task_origin + mix(sub_rect.p0, sub_rect.p1, aPosition.xy),

        0.0,

1.0

);

    gl_Position = uTransform * vertex_pos;

    init_transform_vs(vec4(local_clip_rect.p0, local_clip_rect.p1));

    ClipVertexInfo vi = ClipVertexInfo(local_pos, local_clip_rect);

    return vi;

#endif //WR_VERTEX_SHADER