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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/vr/renderers/radial_gradient_quad_renderer.h"
#include "chrome/browser/vr/elements/corner_radii.h"
#include "chrome/browser/vr/renderers/textured_quad_renderer.h"
#include "device/vr/vr_gl_util.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/size_f.h"
#include "ui/gfx/geometry/transform.h"
namespace vr {
namespace {
static constexpr int kPositionDataSize = 2;
static constexpr size_t kPositionDataOffset = 0;
static constexpr int kOffsetScaleDataSize = 2;
static constexpr size_t kOffsetScaleDataOffset = 2 * sizeof(float);
static constexpr int kCornerPositionDataSize = 2;
static constexpr size_t kCornerPositionDataOffset = 4 * sizeof(float);
static constexpr size_t kDataStride = 6 * sizeof(float);
static constexpr size_t kInnerRectOffset = 6 * sizeof(GLushort);
// clang-format off
static constexpr char const* kVertexShader = SHADER(
precision mediump float;
uniform mat4 u_ModelViewProjMatrix;
uniform vec2 u_ULCornerOffset;
uniform vec2 u_URCornerOffset;
uniform vec2 u_LRCornerOffset;
uniform vec2 u_LLCornerOffset;
uniform mediump float u_AspectRatio;
attribute vec4 a_Position;
attribute vec2 a_CornerPosition;
attribute vec2 a_OffsetScale;
varying vec2 v_CornerPosition;
varying vec2 v_TexCoordinate;
varying vec2 v_Position;
void main() {
v_CornerPosition = a_CornerPosition;
vec2 corner_offset;
if (a_Position[0] < 0.0 && a_Position[1] > 0.0) {
corner_offset = u_ULCornerOffset;
} else if (a_Position[0] > 0.0 && a_Position[1] > 0.0) {
corner_offset = u_URCornerOffset;
} else if (a_Position[0] > 0.0 && a_Position[1] < 0.0) {
corner_offset = u_LRCornerOffset;
} else if (a_Position[0] < 0.0 && a_Position[1] < 0.0) {
corner_offset = u_LLCornerOffset;
}
vec4 position = vec4(
a_Position[0] + corner_offset[0] * a_OffsetScale[0],
a_Position[1] + corner_offset[1] * a_OffsetScale[1],
a_Position[2],
a_Position[3]);
if (u_AspectRatio > 1.0) {
v_Position = vec2(position.x, position.y / u_AspectRatio);
} else {
v_Position = vec2(position.x * u_AspectRatio, position.y);
}
v_TexCoordinate = vec2(0.5 + position[0], 0.5 - position[1]);
gl_Position = u_ModelViewProjMatrix * position;
}
);
static constexpr char const* kFragmentShader = SHADER(
precision highp float;
varying vec2 v_CornerPosition;
varying vec2 v_Position;
varying vec2 v_TexCoordinate;
uniform mediump float u_Opacity;
uniform vec2 u_ClipRect[2];
uniform vec4 u_CenterColor;
uniform vec4 u_EdgeColor;
void main() {
vec2 s = step(u_ClipRect[0], v_TexCoordinate)
- step(u_ClipRect[1], v_TexCoordinate);
float insideClip = s.x * s.y;
vec2 position = v_Position;
float edge_color_weight = clamp(2.0 * length(position), 0.0, 1.0);
float center_color_weight = 1.0 - edge_color_weight;
vec4 color = u_CenterColor * center_color_weight + u_EdgeColor *
edge_color_weight;
float mask = 1.0 - step(1.0, length(v_CornerPosition));
// Add some noise to prevent banding artifacts in the gradient.
float n = (fract(dot(v_Position.xy, vec2(12345.67, 456.7))) - 0.5) / 255.0;
color = color + n;
color = vec4(color.rgb * color.a, color.a);
gl_FragColor = insideClip * color * u_Opacity * mask;
}
);
// clang-format on
void SetCornerOffset(GLuint handle, float radius, const gfx::SizeF& size) {
if (radius == 0.0f)
glUniform2f(handle, 0.0, 0.0);
else
glUniform2f(handle, radius / size.width(), radius / size.height());
}
} // namespace
RadialGradientQuadRenderer::RadialGradientQuadRenderer()
: BaseRenderer(kVertexShader, kFragmentShader) {
model_view_proj_matrix_handle_ =
glGetUniformLocation(program_handle_, "u_ModelViewProjMatrix");
ul_corner_offset_handle_ =
glGetUniformLocation(program_handle_, "u_ULCornerOffset");
ur_corner_offset_handle_ =
glGetUniformLocation(program_handle_, "u_URCornerOffset");
lr_corner_offset_handle_ =
glGetUniformLocation(program_handle_, "u_LRCornerOffset");
ll_corner_offset_handle_ =
glGetUniformLocation(program_handle_, "u_LLCornerOffset");
corner_position_handle_ =
glGetAttribLocation(program_handle_, "a_CornerPosition");
offset_scale_handle_ = glGetAttribLocation(program_handle_, "a_OffsetScale");
opacity_handle_ = glGetUniformLocation(program_handle_, "u_Opacity");
center_color_handle_ = glGetUniformLocation(program_handle_, "u_CenterColor");
edge_color_handle_ = glGetUniformLocation(program_handle_, "u_EdgeColor");
aspect_ratio_handle_ = glGetUniformLocation(program_handle_, "u_AspectRatio");
}
RadialGradientQuadRenderer::~RadialGradientQuadRenderer() = default;
void RadialGradientQuadRenderer::Draw(
const gfx::Transform& model_view_proj_matrix,
SkColor edge_color,
SkColor center_color,
const gfx::RectF& clip_rect,
float opacity,
const gfx::SizeF& element_size,
const CornerRadii& radii) {
DCHECK(opacity > 0.f);
if (SkColorGetA(edge_color) == SK_AlphaTRANSPARENT &&
SkColorGetA(center_color) == SK_AlphaTRANSPARENT) {
return;
}
if (!clip_rect.Intersects(gfx::RectF(1.0f, 1.0f)))
return;
glUseProgram(program_handle_);
glBindBuffer(GL_ARRAY_BUFFER, TexturedQuadRenderer::VertexBuffer());
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, TexturedQuadRenderer::IndexBuffer());
// Set up position attribute.
glVertexAttribPointer(position_handle_, kPositionDataSize, GL_FLOAT, false,
kDataStride, VOID_OFFSET(kPositionDataOffset));
glEnableVertexAttribArray(position_handle_);
// Set up offset scale attribute.
glVertexAttribPointer(offset_scale_handle_, kOffsetScaleDataSize, GL_FLOAT,
false, kDataStride,
VOID_OFFSET(kOffsetScaleDataOffset));
glEnableVertexAttribArray(offset_scale_handle_);
// Set up corner position attribute.
glVertexAttribPointer(corner_position_handle_, kCornerPositionDataSize,
GL_FLOAT, false, kDataStride,
VOID_OFFSET(kCornerPositionDataOffset));
glEnableVertexAttribArray(corner_position_handle_);
SetCornerOffset(ul_corner_offset_handle_, radii.upper_left, element_size);
SetCornerOffset(ur_corner_offset_handle_, radii.upper_right, element_size);
SetCornerOffset(lr_corner_offset_handle_, radii.lower_right, element_size);
SetCornerOffset(ll_corner_offset_handle_, radii.lower_left, element_size);
// Set the edge color to the fog color so that it seems to fade out.
SetColorUniform(edge_color_handle_, edge_color);
SetColorUniform(center_color_handle_, center_color);
glUniform1f(opacity_handle_, opacity);
glUniform1f(aspect_ratio_handle_,
element_size.width() / element_size.height());
// Pass in model view project matrix.
glUniformMatrix4fv(model_view_proj_matrix_handle_, 1, false,
MatrixToGLArray(model_view_proj_matrix).data());
const GLfloat clip_rect_data[4] = {clip_rect.x(), clip_rect.y(),
clip_rect.right(), clip_rect.bottom()};
glUniform2fv(clip_rect_handle_, 2, clip_rect_data);
if (radii.IsZero()) {
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT,
VOID_OFFSET(kInnerRectOffset));
} else {
glDrawElements(GL_TRIANGLES, TexturedQuadRenderer::NumQuadIndices(),
GL_UNSIGNED_SHORT, 0);
}
glDisableVertexAttribArray(position_handle_);
glDisableVertexAttribArray(offset_scale_handle_);
glDisableVertexAttribArray(corner_position_handle_);
}
} // namespace vr
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