fmdsp opengl renderer

2 files changed, 188 insertions, 0 deletions

diff --git a/fmdsp/fmdsp_gl.c b/fmdsp/fmdsp_gl.c
new file mode 100644
index 0000000..7f62a60
--- /dev/null
+++ b/fmdsp/fmdsp_gl.c
@@ -0,0 +1,177 @@
+// supports OpenGL 2.0 / OpenGL ES 2.0
+// when using OpenGL ES, define MYON_OPENGL_ES
+
+#include "myon_opengl.h"
+#include "fmdsp_gl.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef MYON_OPENGL_ES
+static const char sh_version[] = "#version 100\n";
+#else
+static const char sh_version[] = "#version 110\n";
+#endif
+
+static const char v_sh[] =
+  "attribute vec2 coord2d;\n"
+  "varying vec2 texcoord;\n"
+  "uniform float xscale;\n"
+  "uniform float yscale;\n"
+  "void main(void) {\n"
+  "  vec2 coord = coord2d * vec2(xscale, yscale);\n"
+  "  gl_Position = vec4(coord, 0.0, 1.0);\n"
+  "  texcoord = (coord2d + 1.0) / 2.0;\n"
+  "  texcoord = vec2(texcoord.x, 1.0-texcoord.y);\n"
+  "}\n"
+;
+
+#ifdef MYON_OPENGL_ES
+static const char f_sh[] =
+  "uniform sampler2D vram;\n"
+  "uniform sampler2D palette;\n"
+  "varying mediump vec2 texcoord;\n"
+  "void main(void) {\n"
+  "  mediump float index = texture2D(vram, texcoord).x;\n"
+  "  index = index * 256.0 / 9.0;\n"
+  "  gl_FragColor = texture2D(palette, vec2(index, 0.0));\n"
+  "}\n"
+;
+#else
+static const char f_sh[] =
+  "uniform sampler2D vram;\n"
+  "uniform sampler2D palette;\n"
+  "varying vec2 texcoord;\n"
+  "void main(void) {\n"
+  "  float index = texture2D(vram, texcoord).x;\n"
+  "  index = index * 256.0 / 9.0;\n"
+  "  gl_FragColor = texture2D(palette, vec2(index, 0.0));\n"
+  "}\n"
+;
+#endif
+
+static const GLfloat triangle_vertices[] = {
+  -1.0, -1.0,
+  1.0, -1.0,
+  -1.0, 1.0,
+  1.0, 1.0
+};
+
+static GLuint create_shader(const char *shader, GLenum type) {
+  GLuint s = glCreateShader(type);
+  const char *source[2] = {sh_version, shader};
+  glShaderSource(s, 2, source, 0);
+  glCompileShader(s);
+  GLint ok;
+  glGetShaderiv(s, GL_COMPILE_STATUS, &ok);
+  if (!ok) {
+    GLint len;
+    glGetShaderiv(s, GL_INFO_LOG_LENGTH, &len);
+    if (len > 0) {
+      char *log = malloc(len);
+      if (log) {
+        glGetShaderInfoLog(s, len, 0, log);
+        printf("%s shader error: \n%s\n",
+               (type == GL_VERTEX_SHADER) ? "vertex" : "fragment",
+               log);
+        free(log);
+      }
+    }
+    glDeleteShader(s);
+    return 0;
+  }
+  return s;
+}
+
+struct fmdsp_gl {
+  struct fmdsp *fmdsp;
+  GLuint program;
+  GLint attr_coord2d;
+  GLint uni_vram;
+  GLint uni_palette;
+  GLint uni_xscale;
+  GLint uni_yscale;
+  GLuint tex_vram;
+  GLuint tex_palette;
+  uint8_t prev_palette[FMDSP_PALETTE_COLORS*3];
+};
+
+struct fmdsp_gl *fmdsp_gl_init(struct fmdsp *fmdsp, float xscale, float yscale) {
+  struct fmdsp_gl *fmdsp_gl = 0;
+  GLint vs = 0;
+  GLint fs = 0;
+  fmdsp_gl = malloc(sizeof(*fmdsp_gl));
+  if (!fmdsp_gl) goto err;
+  fmdsp_gl->fmdsp = fmdsp;
+  fmdsp_gl->program = glCreateProgram();
+  glGenTextures(1, &fmdsp_gl->tex_vram);
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, fmdsp_gl->tex_vram);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glActiveTexture(GL_TEXTURE1);
+  glGenTextures(1, &fmdsp_gl->tex_palette);
+  glBindTexture(GL_TEXTURE_2D, fmdsp_gl->tex_palette);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  vs = create_shader(v_sh, GL_VERTEX_SHADER);
+  if (!vs) goto err;
+  fs = create_shader(f_sh, GL_FRAGMENT_SHADER);
+  if (!fs) goto err;
+  glAttachShader(fmdsp_gl->program, vs);
+  glAttachShader(fmdsp_gl->program, fs);
+  glLinkProgram(fmdsp_gl->program);
+  GLint ok;
+  glGetProgramiv(fmdsp_gl->program, GL_LINK_STATUS, &ok);
+  if (!ok) {
+    printf("link error\n");
+    goto err;
+  }
+  glUseProgram(fmdsp_gl->program);
+  fmdsp_gl->attr_coord2d = glGetAttribLocation(fmdsp_gl->program, "coord2d");
+  if (fmdsp_gl->attr_coord2d < 0) goto err;
+  fmdsp_gl->uni_vram = glGetUniformLocation(fmdsp_gl->program, "vram");
+  if (fmdsp_gl->uni_vram < 0) goto err;
+  fmdsp_gl->uni_palette = glGetUniformLocation(fmdsp_gl->program, "palette");
+  if (fmdsp_gl->uni_palette < 0) goto err;
+  fmdsp_gl->uni_xscale = glGetUniformLocation(fmdsp_gl->program, "xscale");
+  if (fmdsp_gl->uni_xscale < 0) goto err;
+  fmdsp_gl->uni_yscale = glGetUniformLocation(fmdsp_gl->program, "yscale");
+  if (fmdsp_gl->uni_yscale < 0) goto err;
+  glUniform1i(fmdsp_gl->uni_vram, 0);
+  glUniform1i(fmdsp_gl->uni_palette, 1);
+  glUniform1f(fmdsp_gl->uni_xscale, xscale);
+  glUniform1f(fmdsp_gl->uni_yscale, yscale);
+  glEnableVertexAttribArray(fmdsp_gl->attr_coord2d);
+  glVertexAttribPointer(fmdsp_gl->attr_coord2d,
+                        2, GL_FLOAT, GL_FALSE, 0, triangle_vertices);
+  return fmdsp_gl;
+err:
+  glDeleteShader(vs);
+  glDeleteShader(fs);
+  if (fmdsp_gl) {
+    glDeleteTextures(1, &fmdsp_gl->tex_vram);
+    glDeleteTextures(1, &fmdsp_gl->tex_palette);
+    glDeleteProgram(fmdsp_gl->program);
+  }
+  free(fmdsp_gl);
+  return 0;
+}
+
+void fmdsp_gl_render(struct fmdsp_gl *fmdsp_gl, uint8_t *vram) {
+  glActiveTexture(GL_TEXTURE0);
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, PC98_W, PC98_H, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, vram);
+  if (memcmp(fmdsp_gl->prev_palette, fmdsp_gl->fmdsp->palette, sizeof(fmdsp_gl->prev_palette))) {
+    glActiveTexture(GL_TEXTURE1);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, FMDSP_PALETTE_COLORS, 1, 0, GL_RGB, GL_UNSIGNED_BYTE, fmdsp_gl->fmdsp->palette);
+    memcpy(fmdsp_gl->prev_palette, fmdsp_gl->fmdsp->palette, sizeof(fmdsp_gl->prev_palette));
+  }
+  glClear(GL_COLOR_BUFFER_BIT);
+  glActiveTexture(GL_TEXTURE1);
+  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+  glFlush();
+}
diff --git a/fmdsp/fmdsp_gl.h b/fmdsp/fmdsp_gl.h
new file mode 100644
index 0000000..e279b61
--- /dev/null
+++ b/fmdsp/fmdsp_gl.h
@@ -0,0 +1,11 @@
+#ifndef MYON_FMDSP_GL_H_INCLUDED
+#define MYON_FMDSP_GL_H_INCLUDED
+
+#include "fmdsp/fmdsp.h"
+
+struct fmdsp_gl;
+
+struct fmdsp_gl *fmdsp_gl_init(struct fmdsp *fmdsp, float xscale, float yscale);
+void fmdsp_gl_render(struct fmdsp_gl *fmdsp_gl, uint8_t *vram);
+
+#endif // MYON_FMDSP_GL_H_INCLUDED