iOS render: Handle frame rotation in OpenGL
This CL handles frame rotation by updating the OpenGL vertex data in
RTCOpenGLVideoRenderer, instead of calling the expensive
libyuv::I420Rotate that will rotate the actual memory. Also, we can
handle rotated native frames instead of falling back to
NativeToI420Buffer.
Review-Url: https://codereview.webrtc.org/2176623002
Cr-Commit-Position: refs/heads/master@{#13715}
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCShader.mm b/webrtc/sdk/objc/Framework/Classes/RTCShader.mm
index 8808206..26dc64f 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCShader.mm
+++ b/webrtc/sdk/objc/Framework/Classes/RTCShader.mm
@@ -10,6 +10,8 @@
#import "RTCShader.h"
+#include <algorithm>
+#include <array>
#include <memory>
#import "RTCShader+Private.h"
@@ -28,21 +30,6 @@
" v_texcoord = texcoord;\n"
"}\n";
-// When modelview and projection matrices are identity (default) the world is
-// contained in the square around origin with unit size 2. Drawing to these
-// coordinates is equivalent to drawing to the entire screen. The texture is
-// stretched over that square using texture coordinates (u, v) that range
-// from (0, 0) to (1, 1) inclusive. Texture coordinates are flipped vertically
-// here because the incoming frame has origin in upper left hand corner but
-// OpenGL expects origin in bottom left corner.
-static const GLfloat gVertices[] = {
- // X, Y, U, V.
- -1, -1, 0, 1, // Bottom left.
- 1, -1, 1, 1, // Bottom right.
- 1, 1, 1, 0, // Top right.
- -1, 1, 0, 0, // Top left.
-};
-
// Compiles a shader of the given |type| with GLSL source |source| and returns
// the shader handle or 0 on error.
GLuint RTCCreateShader(GLenum type, const GLchar *source) {
@@ -111,9 +98,8 @@
return program;
}
-// Set vertex shader variables 'position' and 'texcoord' in |program| to the
-// |gVertices| array above. It will use |vertexBuffer| and |vertexArray| to
-// store the vertex data.
+// Set vertex shader variables 'position' and 'texcoord' in |program| to use
+// |vertexBuffer| and |vertexArray| to store the vertex data.
BOOL RTCSetupVerticesForProgram(GLuint program, GLuint* vertexBuffer, GLuint* vertexArray) {
GLint position = glGetAttribLocation(program, "position");
GLint texcoord = glGetAttribLocation(program, "texcoord");
@@ -132,11 +118,11 @@
return NO;
}
glBindBuffer(GL_ARRAY_BUFFER, *vertexBuffer);
- glBufferData(GL_ARRAY_BUFFER, sizeof(gVertices), gVertices, GL_DYNAMIC_DRAW);
+ glBufferData(GL_ARRAY_BUFFER, 4 * 4 * sizeof(GLfloat), NULL, GL_DYNAMIC_DRAW);
- // Read position attribute from |gVertices| with size of 2 and stride of 4
- // beginning at the start of the array. The last argument indicates offset
- // of data within |gVertices| as supplied to the vertex buffer.
+ // Read position attribute with size of 2 and stride of 4 beginning at the
+ // start of the array. The last argument indicates offset of data within the
+ // vertex buffer.
glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat),
(void *)0);
glEnableVertexAttribArray(position);
@@ -150,3 +136,49 @@
return YES;
}
+
+// Set vertex data to the currently bound vertex buffer.
+void RTCSetVertexData(webrtc::VideoRotation rotation) {
+ // When modelview and projection matrices are identity (default) the world is
+ // contained in the square around origin with unit size 2. Drawing to these
+ // coordinates is equivalent to drawing to the entire screen. The texture is
+ // stretched over that square using texture coordinates (u, v) that range
+ // from (0, 0) to (1, 1) inclusive. Texture coordinates are flipped vertically
+ // here because the incoming frame has origin in upper left hand corner but
+ // OpenGL expects origin in bottom left corner.
+ std::array<std::array<GLfloat, 2>, 4> UVCoords = {{
+ {{0, 1}}, // Lower left.
+ {{1, 1}}, // Lower right.
+ {{1, 0}}, // Upper right.
+ {{0, 0}}, // Upper left.
+ }};
+
+ // Rotate the UV coordinates.
+ int rotation_offset;
+ switch (rotation) {
+ case webrtc::kVideoRotation_0:
+ rotation_offset = 0;
+ break;
+ case webrtc::kVideoRotation_90:
+ rotation_offset = 1;
+ break;
+ case webrtc::kVideoRotation_180:
+ rotation_offset = 2;
+ break;
+ case webrtc::kVideoRotation_270:
+ rotation_offset = 3;
+ break;
+ }
+ std::rotate(UVCoords.begin(), UVCoords.begin() + rotation_offset,
+ UVCoords.end());
+
+ const GLfloat gVertices[] = {
+ // X, Y, U, V.
+ -1, -1, UVCoords[0][0], UVCoords[0][1],
+ 1, -1, UVCoords[1][0], UVCoords[1][1],
+ 1, 1, UVCoords[2][0], UVCoords[2][1],
+ -1, 1, UVCoords[3][0], UVCoords[3][1],
+ };
+
+ glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(gVertices), gVertices);
+}