Add push constant graphics tests. (#492)

Currently all the push constant tests are compute based. This CL adds a
graphics push constant test in both VkScript and AmberScript.

(Along the way, the error message for outputting an image buffer was
cleaned up to make it clearer what failed.)

3 files changed, 21 insertions, 11 deletions

diff --git a/samples/png.cc b/samples/png.cc
index bddb3a7..b23e002 100644
--- a/samples/png.cc
+++ b/samples/png.cc
@@ -50,7 +50,11 @@ amber::Result ConvertToPNG(uint32_t width,
                            uint32_t height,
                            const std::vector<amber::Value>& values,
                            std::vector<uint8_t>* buffer) {
-  assert(values.size() == width * height);
+  if (values.size() != (width * height)) {
+    return amber::Result("Values size (" + std::to_string(values.size()) +
+                         ") != " + "width * height (" +
+                         std::to_string(width * height) + ")");
+  }
 
   std::vector<uint8_t> data;
 
diff --git a/samples/ppm.cc b/samples/ppm.cc
index db53835..9cd3ae8 100644
--- a/samples/ppm.cc
+++ b/samples/ppm.cc
@@ -20,7 +20,6 @@
 #include "amber/value.h"
 
 namespace ppm {
-
 namespace {
 
 const uint32_t kMaximumColorValue = 255;
@@ -39,11 +38,15 @@ uint8_t byte2(uint32_t word) {
 
 }  // namespace
 
-void ConvertToPPM(uint32_t width,
-                  uint32_t height,
-                  const std::vector<amber::Value>& values,
-                  std::vector<uint8_t>* buffer) {
-  assert(values.size() == width * height);
+amber::Result ConvertToPPM(uint32_t width,
+                           uint32_t height,
+                           const std::vector<amber::Value>& values,
+                           std::vector<uint8_t>* buffer) {
+  if (values.size() != (width * height)) {
+    return amber::Result("Values size (" + std::to_string(values.size()) +
+                         ") != " + "width * height (" +
+                         std::to_string(width * height) + ")");
+  }
 
   // Write PPM header
   std::string image = "P6\n";
@@ -62,6 +65,8 @@ void ConvertToPPM(uint32_t width,
     buffer->push_back(byte0(pixel));  // B
     // PPM does not support alpha channel
   }
+
+  return {};
 }
 
 }  // namespace ppm
diff --git a/samples/ppm.h b/samples/ppm.h
index b8e680d..0ea01e4 100644
--- a/samples/ppm.h
+++ b/samples/ppm.h
@@ -20,16 +20,17 @@
 #include <vector>
 
 #include "amber/amber.h"
+#include "amber/result.h"
 
 namespace ppm {
 
 /// Converts the image of dimensions |width| and |height| and with pixels stored
 /// in row-major order in |values| with format B8G8R8A8 into PPM format,
 /// returning the PPM binary in |buffer|.
-void ConvertToPPM(uint32_t width,
-                  uint32_t height,
-                  const std::vector<amber::Value>& values,
-                  std::vector<uint8_t>* buffer);
+amber::Result ConvertToPPM(uint32_t width,
+                           uint32_t height,
+                           const std::vector<amber::Value>& values,
+                           std::vector<uint8_t>* buffer);
 
 }  // namespace ppm