+// Take a copy of the flow, bilinearly interpolated and scaled up.
+class ResizeFlow {
+public:
+ ResizeFlow();
+ void exec(GLuint in_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height);
+
+private:
+ GLuint resize_flow_vs_obj;
+ GLuint resize_flow_fs_obj;
+ GLuint resize_flow_program;
+ GLuint resize_flow_vao;
+
+ GLuint uniform_flow_tex;
+ GLuint uniform_scale_factor;
+};
+
+ResizeFlow::ResizeFlow()
+{
+ resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
+ resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER);
+ resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj);
+
+ // Set up the VAO containing all the required position/texcoord data.
+ glCreateVertexArrays(1, &resize_flow_vao);
+ glBindVertexArray(resize_flow_vao);
+ glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
+
+ GLint position_attrib = glGetAttribLocation(resize_flow_program, "position");
+ glEnableVertexArrayAttrib(resize_flow_vao, position_attrib);
+ glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
+
+ uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex");
+ uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor");
+}
+
+void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height)
+{
+ glUseProgram(resize_flow_program);
+
+ bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
+
+ glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height);
+
+ GLuint resize_flow_fbo; // TODO: cleanup
+ glCreateFramebuffers(1, &resize_flow_fbo);
+ glNamedFramebufferTexture(resize_flow_fbo, GL_COLOR_ATTACHMENT0, out_tex, 0);
+
+ glViewport(0, 0, output_width, output_height);
+ glDisable(GL_BLEND);
+ glBindVertexArray(resize_flow_vao);
+ glBindFramebuffer(GL_FRAMEBUFFER, resize_flow_fbo);
+
+ glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+}
+